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Dr. Suo Yang
Department of Mechanical Engineering, University of Minnesota - Twin Cities, Minneapolis, MN 55455, USA

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Research Keywords & Expertise

0 Computational Fluid Dynamics (CFD)
0 Machine Learning
0 hypersonics
0 turbulent combustion
0 Numerical methods for partial differential equations

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Computational Fluid Dynamics (CFD)
turbulent combustion

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Preprint content
Published: 16 July 2021
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ACS Style

Roshan Rangarajan; Hongyuan Zhang; Alison Hoxie; Paul Strykowski; Suo Yang; Vinod Srinivasan. Atomization of High Viscosity Liquids Using a Two-Fluid Counterflow Nozzle: Experiments and Modeling. 2021, 1 .

AMA Style

Roshan Rangarajan, Hongyuan Zhang, Alison Hoxie, Paul Strykowski, Suo Yang, Vinod Srinivasan. Atomization of High Viscosity Liquids Using a Two-Fluid Counterflow Nozzle: Experiments and Modeling. . 2021; ():1.

Chicago/Turabian Style

Roshan Rangarajan; Hongyuan Zhang; Alison Hoxie; Paul Strykowski; Suo Yang; Vinod Srinivasan. 2021. "Atomization of High Viscosity Liquids Using a Two-Fluid Counterflow Nozzle: Experiments and Modeling." , no. : 1.

Journal article
Published: 01 March 2021 in Physics of Fluids
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The ongoing COVID-19 pandemic has shifted attention to the airborne transmission of exhaled droplet nuclei within indoor environments. The spread of aerosols through singing and musical instruments in music performances has necessitated precautionary methods such as masks and portable purifiers. This study investigates the effects of placing portable air purifiers at different locations inside a classroom and the effects of different aerosol injection rates (e.g., with and without masks, different musical instruments, and different injection modes). Aerosol deposition, airborne concentration, and removal are analyzed in this study. It was found that using purifiers could help in achieving ventilation rates close to the prescribed values by the World Health Organization, while also achieving aerosol removal times within the Center of Disease Control and Prevention recommended guidelines. This could help in deciding break periods between classroom sessions, which was around 25 min through this study. Moreover, proper placement of purifiers could offer significant advantages in reducing airborne aerosol numbers (offering several orders of magnitude higher aerosol removal when compared to nearly zero removal when having no purifiers), and improper placement of the purifiers could worsen the situation. This study suggests the purifier to be placed close to the injector to yield a benefit and away from the people to be protected. The injection rate was found to have an almost linear correlation with the average airborne aerosol suspension rate and deposition rate, which could be used to predict the trends for scenarios with other injection rates.

ACS Style

Sai Ranjeet Narayanan; Suo Yang. Airborne transmission of virus-laden aerosols inside a music classroom: Effects of portable purifiers and aerosol injection rates. Physics of Fluids 2021, 33, 033307 .

AMA Style

Sai Ranjeet Narayanan, Suo Yang. Airborne transmission of virus-laden aerosols inside a music classroom: Effects of portable purifiers and aerosol injection rates. Physics of Fluids. 2021; 33 (3):033307.

Chicago/Turabian Style

Sai Ranjeet Narayanan; Suo Yang. 2021. "Airborne transmission of virus-laden aerosols inside a music classroom: Effects of portable purifiers and aerosol injection rates." Physics of Fluids 33, no. 3: 033307.

Journal article
Published: 18 January 2021 in Combustion and Flame
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One of the major concerns in high pressure combustion is its high soot yield. An exact and comprehensive mechanism behind this phenomenon, from a chemical kinetics perspective, is still elusive. In this study, a series of pressurized (1–16 atm) co-flow ethylene diffusion sooting flames are simulated with detailed finite-rate chemistry and molecular transport. The experimental maximum soot volume fraction and its scaling law with pressure are well reproduced by the simulations. To extract kinetic information from the complex sooting reacting system, a Soot-based Global Pathway Analysis (SGPA) method is developed to identify the dominant Global Pathways (GPs) from fuel to soot by considering carbon element flux from gaseous species to soot. Using SGPA, the dominance and sensitivity of soot chemical pathways at elevated pressures are revealed. It is found that increasing pressure shifts the first ring Polycyclic Aromatic Hydrocarbon (PAH) formation from C3H3 recombination to reactions involving C2H2. At 1 atm, the production of C2H2 for surface growth is purely controlled by the H-abstraction of C2H4 and C2H3. In contrast, at elevated pressures, the production of C2H2 for surface growth is also influenced by many other reactions including some third body reactions. The SGPA method reveals that the mismatch of predicted PAH with the experimental data at 12 atm is majorly caused by the rate coefficient uncertainty of the reaction C2H2 + A1CH2 = C9H8 + H. Based on the analysis by SGPA, the mechanism reduction based on Directed Relation Graph with Error Propagation (DRGEP) with A2 and C2H2 as the target species deleted significant species such as C9H8, C9H7, incurring inaccurate soot field prediction. It is also found that the combined dominance of GPs with heavier PAH species (A4-A7) is even greater than the most dominant GP at the flame wing regions, indicating that heavier PAH species play critical roles for soot nucleation and condensation, especially at the flame wing regions.

ACS Style

Dezhi Zhou; Suo Yang. Soot-based Global Pathway Analysis: Soot formation and evolution at elevated pressures in co-flow diffusion flames. Combustion and Flame 2021, 227, 255 -270.

AMA Style

Dezhi Zhou, Suo Yang. Soot-based Global Pathway Analysis: Soot formation and evolution at elevated pressures in co-flow diffusion flames. Combustion and Flame. 2021; 227 ():255-270.

Chicago/Turabian Style

Dezhi Zhou; Suo Yang. 2021. "Soot-based Global Pathway Analysis: Soot formation and evolution at elevated pressures in co-flow diffusion flames." Combustion and Flame 227, no. : 255-270.

Conference paper
Published: 04 January 2021 in AIAA Scitech 2021 Forum
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ACS Style

Taaresh Sanjeev Taneja; Suo Yang. Numerical Modeling of Plasma Assisted Pyrolysis and Combustion of Ammonia. AIAA Scitech 2021 Forum 2021, 1 .

AMA Style

Taaresh Sanjeev Taneja, Suo Yang. Numerical Modeling of Plasma Assisted Pyrolysis and Combustion of Ammonia. AIAA Scitech 2021 Forum. 2021; ():1.

Chicago/Turabian Style

Taaresh Sanjeev Taneja; Suo Yang. 2021. "Numerical Modeling of Plasma Assisted Pyrolysis and Combustion of Ammonia." AIAA Scitech 2021 Forum , no. : 1.

Conference paper
Published: 04 January 2021 in AIAA Scitech 2021 Forum
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ACS Style

Dezhi Zhou; Anders Vaage; Wesley R. Boyette; Thibault Guiberti; William L. Roberts; Suo Yang. A Numerical Study on Soot Formation and Evolution in Pressurized Turbulent Sooting Flames. AIAA Scitech 2021 Forum 2021, 1 .

AMA Style

Dezhi Zhou, Anders Vaage, Wesley R. Boyette, Thibault Guiberti, William L. Roberts, Suo Yang. A Numerical Study on Soot Formation and Evolution in Pressurized Turbulent Sooting Flames. AIAA Scitech 2021 Forum. 2021; ():1.

Chicago/Turabian Style

Dezhi Zhou; Anders Vaage; Wesley R. Boyette; Thibault Guiberti; William L. Roberts; Suo Yang. 2021. "A Numerical Study on Soot Formation and Evolution in Pressurized Turbulent Sooting Flames." AIAA Scitech 2021 Forum , no. : 1.

Conference paper
Published: 04 January 2021 in AIAA Scitech 2021 Forum
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ACS Style

Krishna Chandra C. Bavandla; Abhinav Tripathi; Dezhi Zhou; Zongxuan Sun; Suo Yang. Comparison between Flat and Creviced Pistons in a Controlled Trajectory Rapid Compression and Expansion Machine (CT-RCEM). AIAA Scitech 2021 Forum 2021, 1 .

AMA Style

Krishna Chandra C. Bavandla, Abhinav Tripathi, Dezhi Zhou, Zongxuan Sun, Suo Yang. Comparison between Flat and Creviced Pistons in a Controlled Trajectory Rapid Compression and Expansion Machine (CT-RCEM). AIAA Scitech 2021 Forum. 2021; ():1.

Chicago/Turabian Style

Krishna Chandra C. Bavandla; Abhinav Tripathi; Dezhi Zhou; Zongxuan Sun; Suo Yang. 2021. "Comparison between Flat and Creviced Pistons in a Controlled Trajectory Rapid Compression and Expansion Machine (CT-RCEM)." AIAA Scitech 2021 Forum , no. : 1.

Conference paper
Published: 04 January 2021 in AIAA Scitech 2021 Forum
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Due to the development of computational capability for reacting flows nowadays, more and more detailed and large-sized information and data are generated by reacting flow simulations. To extract meaningful information from these data sets, computational diagnostic methods are critical, especially when detailed chemistry with thousands of reactions are involved. In this study, in light of the methods of chemical explosive mode analysis (CEMA) and global pathway analysis (GPA), we proposed a hybrid CEMA-GPA method, the CEMA-aided GPA (CGPA) method, to not only understand the combustion modes and the contributing reactions and species, but also achieve a global representation of the chemical kinetics that contribute the most to the local explosiveness. Based on this newly-developed CGPA, a one dimensional (1D) premixed flame is firstly simulated and analyzed, showing that CGPA is able to capture the diffusion assisted ignition mode in this flame. More importantly, the global reaction pathways at different positions are identified and the reactions and radical production associated with the global pathways are extracted to understand the flame structure and chemical kinetics. A three dimensional (3D) piloted turbulent jet flame (Sandia Flame D) is then simulated and analyzed with CGPA.

ACS Style

Dezhi Zhou; Hongyuan Zhang; Suo Yang. Computational Diagnostics for Reacting Flows with Global Pathway Analysis Aided by Chemical Explosive Mode Analysis. AIAA Scitech 2021 Forum 2021, 1 .

AMA Style

Dezhi Zhou, Hongyuan Zhang, Suo Yang. Computational Diagnostics for Reacting Flows with Global Pathway Analysis Aided by Chemical Explosive Mode Analysis. AIAA Scitech 2021 Forum. 2021; ():1.

Chicago/Turabian Style

Dezhi Zhou; Hongyuan Zhang; Suo Yang. 2021. "Computational Diagnostics for Reacting Flows with Global Pathway Analysis Aided by Chemical Explosive Mode Analysis." AIAA Scitech 2021 Forum , no. : 1.

Conference paper
Published: 04 January 2021 in AIAA Scitech 2021 Forum
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ACS Style

Hongyuan Zhang; Suo Yang. Multi-component transcritical flow simulation based on in situ adaptive tabulation of vapor-liquid equilibrium solutions. AIAA Scitech 2021 Forum 2021, 1 .

AMA Style

Hongyuan Zhang, Suo Yang. Multi-component transcritical flow simulation based on in situ adaptive tabulation of vapor-liquid equilibrium solutions. AIAA Scitech 2021 Forum. 2021; ():1.

Chicago/Turabian Style

Hongyuan Zhang; Suo Yang. 2021. "Multi-component transcritical flow simulation based on in situ adaptive tabulation of vapor-liquid equilibrium solutions." AIAA Scitech 2021 Forum , no. : 1.

Preprint content
Published: 22 December 2020
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The ongoing COVID-19 pandemic has shifted attention to the airborne transmission of exhaled droplet nuclei within indoor environments. The spread of aerosols through singing and musical instruments in music performances has necessitated precautionary methods such as masks and portable purifiers. This study investigates the effects of placing portable air purifiers at different locations inside a classroom, as well as the effects of different aerosol injection rates (e.g., with and without masks, different musical instruments and different injection modes). Aerosol deposition, airborne concentration and removal are analyzed in this study. It was found that using purifiers could help in achieving ventilation rates close to the prescribed values by the World Health Organization (WHO), while also achieving aerosol removal times within the Center of Disease Control and Prevention (CDC) recommended guidelines. This could help in deciding break periods between classroom sessions, which was around 25 minutes through this study. Moreover, proper placement of purifiers could offer significant advantages in reducing airborne aerosol numbers (offering orders of magnitude higher aerosol removal when compared to nearly zero removal when having no purifiers), and improper placement of the purifiers could worsen the situation. The study suggests the purifier to be placed close to the injector to yield a benefit, and away from the people to be protected. The injection rate was found to have an almost linear correlation with the average airborne aerosol suspension rate and deposition rate, which could be used to predict the trends for scenarios with other injection rates.

ACS Style

Sai Ranjeet Narayanan; Suo Yang. Airborne Transmission of Virus-Laden Aerosols inside a Music Classroom: Effects of Portable Purifiers and Aerosol Injection Rates. 2020, 1 .

AMA Style

Sai Ranjeet Narayanan, Suo Yang. Airborne Transmission of Virus-Laden Aerosols inside a Music Classroom: Effects of Portable Purifiers and Aerosol Injection Rates. . 2020; ():1.

Chicago/Turabian Style

Sai Ranjeet Narayanan; Suo Yang. 2020. "Airborne Transmission of Virus-Laden Aerosols inside a Music Classroom: Effects of Portable Purifiers and Aerosol Injection Rates." , no. : 1.

Conference paper
Published: 26 September 2020 in Proceedings of the Combustion Institute
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This study investigates the plasma properties and chemical kinetics of plasma-assisted methane reforming in a He diluted nanosecond-pulsed plane-to-plane dielectric barrier discharge (ns-DBD) through the combination of time-resolved in situ laser diagnostics and a 1-D numerical model. Plasma-assisted fuel reforming kinetic mechanisms have predominantly been evaluated on the basis of matching reactant conversion and syngas production to steady-state measurements, which cannot describe the full range of chemistry and physics necessary to validate the model. It was found that adding 1% CH4 to a pure He ns-DBD led to a faster breakdown along the rising edge of the applied voltage pulse, thereby lowering the reduced electric field (E/N), electron number density, and electron temperature. Further addition of CH4 did not continue to alter the E/N in the model. Laser absorption spectroscopy was used to measure gas temperature, C2H2, H2O, and CH2O in a CH4/CO2/He discharge to serve as validation targets for the predicted reaction pathways. CH2O was predicted within 25% of the measured value, while H2O and C2H2 were under-predicted by a factor of two and three, respectively. From path flux analysis, the major pathway for CH2O formation was through the reaction between CH3 and O, while C2H2 formation had multi-step pathways that relied on ions like CH3+ and C2H5+. The path flux analysis also shows that CH2 is a significant intermediate for production of both CH2O and C2H2, and increased CH2 concentration could improve model predictions. The results show that the use of reaction rate constants with lower uncertainties and inclusion of He2+ are needed to improve the predictions. Finally, varying the ”equivalence ratio”, defined by the CH4 dry reforming reaction to H2 and CO, from 0.5 to 2 was shown to have a weak effect on measured product species and experimental trends were explained based on pathways extracted from the model.

ACS Style

Timothy Y. Chen; Taaresh S. Taneja; Aric C. Rousso; Suo Yang; Egemen Kolemen; Yiguang Ju. Time-resolved in situ measurements and predictions of plasma-assisted methane reforming in a nanosecond-pulsed discharge. Proceedings of the Combustion Institute 2020, 38, 6533 -6540.

AMA Style

Timothy Y. Chen, Taaresh S. Taneja, Aric C. Rousso, Suo Yang, Egemen Kolemen, Yiguang Ju. Time-resolved in situ measurements and predictions of plasma-assisted methane reforming in a nanosecond-pulsed discharge. Proceedings of the Combustion Institute. 2020; 38 (4):6533-6540.

Chicago/Turabian Style

Timothy Y. Chen; Taaresh S. Taneja; Aric C. Rousso; Suo Yang; Egemen Kolemen; Yiguang Ju. 2020. "Time-resolved in situ measurements and predictions of plasma-assisted methane reforming in a nanosecond-pulsed discharge." Proceedings of the Combustion Institute 38, no. 4: 6533-6540.

Conference paper
Published: 21 September 2020 in Volume 4B: Combustion, Fuels, and Emissions
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We study the enhanced atomization of viscous liquids by employing a novel two-fluid atomizer. The nozzle establishes a countercurrent flow configuration in which the gas and liquid are directed in opposite directions, establishing a two-phase mixing layer. Detailed measurements of droplet size distributions were carried out using laser shadowgraphy, along with high speed flow visualization. The measurements suggest that the liquid emerges as a spray with little further secondary atomization. The performance of this nozzle is compared to the ‘flow-blurring’ nozzle studied by other investigators for four test liquids of viscosity ranging from 1 to 133.5 mPa.s. The counterflow nozzle produces a spray whose characteristics are relatively insensitive to fluid viscosity over the range studied, for gas-liquid mass flow ratios between 0.25 and 1. To gain insight into the mixing process inside the nozzle, simulations are carried out using an Eulerian-Eulerian Volume of Fluid (VoF) approach for representative experimental conditions. The simulation reveals the detailed process of self-sustained flow oscillations and the physical mechanism that generate liquid filaments and final droplets.

ACS Style

Roshan Rangarajan; Hongyuan Zhang; Paul J. Strykowski; Alison Hoxie; Suo Yang; Vinod Srinivasan. Atomization of High Viscosity Liquids Using a Two-Fluid Counterflow Nozzle: Experiments and Modeling. Volume 4B: Combustion, Fuels, and Emissions 2020, 1 .

AMA Style

Roshan Rangarajan, Hongyuan Zhang, Paul J. Strykowski, Alison Hoxie, Suo Yang, Vinod Srinivasan. Atomization of High Viscosity Liquids Using a Two-Fluid Counterflow Nozzle: Experiments and Modeling. Volume 4B: Combustion, Fuels, and Emissions. 2020; ():1.

Chicago/Turabian Style

Roshan Rangarajan; Hongyuan Zhang; Paul J. Strykowski; Alison Hoxie; Suo Yang; Vinod Srinivasan. 2020. "Atomization of High Viscosity Liquids Using a Two-Fluid Counterflow Nozzle: Experiments and Modeling." Volume 4B: Combustion, Fuels, and Emissions , no. : 1.

Journal article
Published: 16 September 2020 in Journal of Aerosol Science
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The lack of quantitative risk assessment of airborne transmission of COVID-19 under practical settings leads to large uncertainties and inconsistencies in our preventive measures. Combining in situ measurements and computational fluid dynamics simulations, we quantify the exhaled particles from normal respiratory behaviors and their transport under elevator, small classroom, and supermarket settings to evaluate the risk of inhaling potentially virus-containing particles. Our results show that the design of ventilation is critical for reducing the risk of particle encounters. Inappropriate design can significantly limit the efficiency of particle removal, create local hot spots with orders of magnitude higher risks, and enhance particle deposition causing surface contamination. Additionally, our measurements reveal the presence of a substantial fraction of faceted particles from normal breathing and its strong correlation with breathing depth.

ACS Style

Siyao Shao; Dezhi Zhou; Ruichen He; Jiaqi Li; Shufan Zou; Kevin Mallery; Santosh Kumar; Suo Yang; Jiarong Hong. Risk assessment of airborne transmission of COVID-19 by asymptomatic individuals under different practical settings. Journal of Aerosol Science 2020, 151, 105661 -105661.

AMA Style

Siyao Shao, Dezhi Zhou, Ruichen He, Jiaqi Li, Shufan Zou, Kevin Mallery, Santosh Kumar, Suo Yang, Jiarong Hong. Risk assessment of airborne transmission of COVID-19 by asymptomatic individuals under different practical settings. Journal of Aerosol Science. 2020; 151 ():105661-105661.

Chicago/Turabian Style

Siyao Shao; Dezhi Zhou; Ruichen He; Jiaqi Li; Shufan Zou; Kevin Mallery; Santosh Kumar; Suo Yang; Jiarong Hong. 2020. "Risk assessment of airborne transmission of COVID-19 by asymptomatic individuals under different practical settings." Journal of Aerosol Science 151, no. : 105661-105661.

Journal article
Published: 16 July 2020 in Combustion and Flame
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Polycyclic Aromatic Hydrocarbons (PAH) are confined to spatially intermittent regions of low scalar dissipation rates due to their slow formation chemistry. The length scales of these regions are on the order of the Kolmogorov scale or smaller, where molecular diffusion dominates over turbulent mixing irrespective of the large-scale turbulent Reynolds number. A strain-sensitivity parameter is proposed to identify such species. A Strain-Sensitive Transport Approach (SSTA) is then developed to model this differential transport in the nonpremixed flamelet equations. Specifically, the strain-sensitive species are modeled with their non-unity molecular effective Lewis numbers, while the remaining species are modeled with unity effective Lewis numbers. An a priori analysis of nonpremixed flamelet solutions reveals that the flame temperature and strain-insensitive species (e.g., major products of combustion, acetylene, etc.) profiles from the proposed SSTA closely match those from the unity effective Lewis number approach, but the mass fractions of strain-sensitive species (e.g., naphthalene) are significantly modified compared to the unity effective Lewis number approach and are consistent with Direct Numerical Simulation (DNS) data. This new SSTA model is implemented within a Large Eddy Simulation (LES) framework, applied to a series of laboratory-scale turbulent nonpremixed sooting jet flames, and validated via comparisons with experimental measurements of temperature and soot volume fraction. Both the unity effective Lewis number approach and SSTA model provide temperature predictions in good agreement with the experimental data, but the non-unity molecular effective Lewis number approach overpredicts the flame length. Compared to the unity effective Lewis number approach, the spatial distribution of soot volume fraction predicted by SSTA is in better agreement with the experimental measurements in terms of the upstream growth of the soot volume fraction and the location of its peak value along the centerline, both of which strongly depend on accurate predictions of the PAH mass fraction. The maximum soot volume fraction is minimally influenced and in good agreement with the experimental measurements. Finally, with this new SSTA model, the influence of global strain rate on turbulent nonpremixed sooting jet flames is analyzed to find that, even though PAH is inversely proportional to the global strain rate, the soot volume fraction may not be inversely proportional to the global strain rate due to an increase in the acetylene surface growth rate coefficient with global strain rate.

ACS Style

Suo Yang; Jeffry K. Lew; Michael E. Mueller. Large Eddy Simulation of soot evolution in turbulent reacting flows: Strain-Sensitive Transport Approach for Polycyclic Aromatic Hydrocarbons. Combustion and Flame 2020, 220, 219 -234.

AMA Style

Suo Yang, Jeffry K. Lew, Michael E. Mueller. Large Eddy Simulation of soot evolution in turbulent reacting flows: Strain-Sensitive Transport Approach for Polycyclic Aromatic Hydrocarbons. Combustion and Flame. 2020; 220 ():219-234.

Chicago/Turabian Style

Suo Yang; Jeffry K. Lew; Michael E. Mueller. 2020. "Large Eddy Simulation of soot evolution in turbulent reacting flows: Strain-Sensitive Transport Approach for Polycyclic Aromatic Hydrocarbons." Combustion and Flame 220, no. : 219-234.

Journal article
Published: 08 July 2020 in International Journal of Heat and Mass Transfer
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Direct numerical simulations have been adopted to study the turbulent heat transfer in forced convections of supercritical water at two different supercritical pressures P=23 MPa and P=25 MPa in a heated pipe with constant wall heat flux and a bulk Reynolds number of Re0=5400. The present study aims to reveal the mechanisms of turbulent heat transfer of superciritical fluids at different pressures in a spatial-developing flow. The results show that at the smaller pressure ratio Pr=P/Pc, where Pc is the critical pressure, the property variations become more drastic, and both the skin friction coefficient and Nusselt number become smaller. The decompositions of skin friction and Nusselt number show that it is mainly due to the large turbulence reduction along the streamwise direction. The analyses of turbulent kinetic energy (TKE), the turbulent shear stress, and the production of TKE confirm this point. Moreover, it was found that the thermophysical property fluctuations are very large and significantly influence the turbulent statistics in the supercritical fluid flows. Due to the large property fluctuations, it was found that the density-fluctuation-related terms are significant and their values are actually comparable to the mean-density-related terms. Due to their negative contributions to turbulent shear stress and turbulent heat flux, the turbulence and heat transfer are severely attenuated by the large thermophysical property fluctuations. For near-wall scaling in spatial-developing flows at supercritical pressures, the semi-local velocity transformation with a semi-local coordinate shows a better agreement in the logarithmic region. However, a clear deviation still exists, especially for mean temperature because all the transformations only incorporate the local mean property variations and cannot consider their fluctuations.

ACS Style

Jiaming Liu; Pinghui Zhao; Mingzhun Lei; Suo Yang; Hassan Nemati. Numerical investigation of spatial-developing turbulent heat transfer in forced convections at different supercritical pressures. International Journal of Heat and Mass Transfer 2020, 159, 120128 .

AMA Style

Jiaming Liu, Pinghui Zhao, Mingzhun Lei, Suo Yang, Hassan Nemati. Numerical investigation of spatial-developing turbulent heat transfer in forced convections at different supercritical pressures. International Journal of Heat and Mass Transfer. 2020; 159 ():120128.

Chicago/Turabian Style

Jiaming Liu; Pinghui Zhao; Mingzhun Lei; Suo Yang; Hassan Nemati. 2020. "Numerical investigation of spatial-developing turbulent heat transfer in forced convections at different supercritical pressures." International Journal of Heat and Mass Transfer 159, no. : 120128.

Articles
Published: 24 April 2020 in Combustion Science and Technology
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In this study, large eddy simulations (LES) are conducted using both a finite-rate chemistry (FRC) model and a flamelet/progress-variable (FPV) model for a series of piloted partially premixed methane/air flames of increasing turbulence intensity (Sandia Flames D, E, and F). From Flame D to E to F, as flow velocity and strain rate increase, the flame is either pushed downstream and extended radially or weakened by enhanced local extinction. The two combustion models produce different spatial distributions of both time-averaged quantities and instantaneous flame field. The FPV model provides an overall better prediction of the time-averaged axial and radial profiles of Flame D, but a significantly worse prediction of Flame F, primarily because the FPV model significantly over predicts local extinction. In terms of the conditional statistics, in which the effects of spatial distribution of mixture fraction and subgrid-scale (SGS) modeling are largely “removed,” the FRC model provides better predictions than the FPV model for all quantities at most locations and mixture fractions in all three flames. The effect of differential diffusion on the prediction of a species depends on the molecular diffusivity of that species; the effect is typically smaller than the difference between the FRC and FPV models.

ACS Style

Suo Yang; Xingjian Wang; Wenting Sun; Vigor Yang. Comparison of Finite Rate Chemistry and Flamelet/Progress-Variable Models: Sandia Flames and the Effect of Differential Diffusion. Combustion Science and Technology 2020, 192, 1137 -1159.

AMA Style

Suo Yang, Xingjian Wang, Wenting Sun, Vigor Yang. Comparison of Finite Rate Chemistry and Flamelet/Progress-Variable Models: Sandia Flames and the Effect of Differential Diffusion. Combustion Science and Technology. 2020; 192 (7):1137-1159.

Chicago/Turabian Style

Suo Yang; Xingjian Wang; Wenting Sun; Vigor Yang. 2020. "Comparison of Finite Rate Chemistry and Flamelet/Progress-Variable Models: Sandia Flames and the Effect of Differential Diffusion." Combustion Science and Technology 192, no. 7: 1137-1159.

Conference paper
Published: 05 January 2020 in AIAA Scitech 2020 Forum
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A 1D numerical model has been developed for a capacitively-coupled RF parallel plate argon-silane dusty plasma. The Hybrid Method of Moments has been used to solve the aerosol population balance equations. The aerosol module is self consistently coupled with a plasma module. This simplified model treats the nucleation and surface growth rates as input parameters. Operating conditions include 13.56 MHz frequency, applied RF voltage of 65 V, 17 Pa pressure, 4-cm electrode gap, grounded bottom electrode, showerhead-type top electrode with gas flow consisting of a 30:1 argon silane ratio. Simulation results are presented and compared with the results of a corresponding sectional method under the same test conditions.

ACS Style

Sai R. Narayanan; Suo Yang; Steven L. Girshick. Hybrid Method of Moments to Predict Nanoparticle Nucleation, Growth and Charging in Dusty Plasmas. AIAA Scitech 2020 Forum 2020, 1 .

AMA Style

Sai R. Narayanan, Suo Yang, Steven L. Girshick. Hybrid Method of Moments to Predict Nanoparticle Nucleation, Growth and Charging in Dusty Plasmas. AIAA Scitech 2020 Forum. 2020; ():1.

Chicago/Turabian Style

Sai R. Narayanan; Suo Yang; Steven L. Girshick. 2020. "Hybrid Method of Moments to Predict Nanoparticle Nucleation, Growth and Charging in Dusty Plasmas." AIAA Scitech 2020 Forum , no. : 1.

Conference paper
Published: 05 January 2020 in AIAA Scitech 2020 Forum
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A non-equilibrium Langmuir-Knudsen model for multi-component pure diesel and blended diesel/alcohol droplets is developed. This model takes into account most of the key processes during the droplet lifetime, including the finite heat conduction and limited mass diffusion inside the droplet, the differential diffusion in gas phase, and the non-equilibrium Langmuir-Knudsen evaporation law for multi-component droplets. The present model shows good agreements with experimental measurements for pure ethanol, diesel, and blended diesel/ethanol droplets. The non-equilibrium effects become significant when the initial droplet diameter is smaller than 20 μm, and these effects are enhanced with increasing ambient temperature and forced convection intensity. The non-equilibrium effects are more significant for the blended diesel/alcohol droplets than pure diesel, especially during the evaporation period of ethanol.

ACS Style

Ping Yi; Hongyuan Zhang; Suo Yang. Evaluation of a non-equilibrium multi-component evaporation model for blended diesel/alcohol droplets. AIAA Scitech 2020 Forum 2020, 1 .

AMA Style

Ping Yi, Hongyuan Zhang, Suo Yang. Evaluation of a non-equilibrium multi-component evaporation model for blended diesel/alcohol droplets. AIAA Scitech 2020 Forum. 2020; ():1.

Chicago/Turabian Style

Ping Yi; Hongyuan Zhang; Suo Yang. 2020. "Evaluation of a non-equilibrium multi-component evaporation model for blended diesel/alcohol droplets." AIAA Scitech 2020 Forum , no. : 1.

Conference paper
Published: 05 January 2020 in AIAA Scitech 2020 Forum
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In this study, a reacting flow solver with detailed transport, chemistry and steady-state preserving splitting schemes based on OpenFOAM (OF) and Cantera is developed. To address the existing issues in the current OF platform, Cantera package is coupled with OF so that the chemistry reader, chemistry model and species transport properties handled by Cantera could be accessed by OF. In this way, the simplified transport model and inaccurate ordinary differential equation (ODE) solver in OF can be replaced by the more detailed transport model and reliable CVODE solver. More importantly, two steady-state preserving splitting schemes are implemented in this new solver, showing better accuracy than the existing OF splitting way. The newly added features in this new solver is assessed and validated with a series of auto-ignition, unsteady perfectly stirred reactor and counter flow diffusion flame cases.

ACS Style

Dezhi Zhou; Suo Yang. A robust reacting flow solver with detailed transport, chemistry, and steady-state preserving splitting schemes based on OpenFOAM and Cantera. AIAA Scitech 2020 Forum 2020, 1 .

AMA Style

Dezhi Zhou, Suo Yang. A robust reacting flow solver with detailed transport, chemistry, and steady-state preserving splitting schemes based on OpenFOAM and Cantera. AIAA Scitech 2020 Forum. 2020; ():1.

Chicago/Turabian Style

Dezhi Zhou; Suo Yang. 2020. "A robust reacting flow solver with detailed transport, chemistry, and steady-state preserving splitting schemes based on OpenFOAM and Cantera." AIAA Scitech 2020 Forum , no. : 1.

Conference paper
Published: 05 January 2020 in AIAA Scitech 2020 Forum
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In conventional internal combustion engines, due to the unstable and “unpredictable” turbulent combustion phenomena, heavy crank shafts are used to ensure stable and robust operations by their large inertia. Such heavy crank shafts limit the flexibility of the piston motion such as compression ratio, which is a bottleneck for the improvement in fuel economy. In addition, the piston trajectory is fixed for all operation conditions (i.e., speed and load). Based on the recent advance in control system capacity and the better understanding of combustion and turbulence, we can potentially remove the heavy crank shafts to enhance engine efficiency and can use variable piston trajectories and compression ratios to match with the unstable combustion processes (similar to a free piston engine) and to attain robust operations. The key to enable such engines is an accurate prediction of the combustion responses to provide effective feedback signals for the advanced control system. As an early stage investigation of such operations, in this study, several piston trajectories and compression ratios are simulated for a controlled trajectory rapid compression and expansion machine (CT-RCEM). First, pure diluent gases are simulated to illustrate the turbulent flow evolution and vortex generation under different piston trajectories. Second, lean fuel-air mixtures are simulated to capture the auto-ignition and combustion under the same trajectories. Local pressure prediction is compared with the experimental data for model validation.

ACS Style

Krishna C. Bavandla; Dezhi Zhou; Abhinav Tripathi; Zongxuan Sun; Suo Yang. Numerical Simulation of a Controlled Trajectory Rapid Compression Machine. AIAA Scitech 2020 Forum 2020, 1 .

AMA Style

Krishna C. Bavandla, Dezhi Zhou, Abhinav Tripathi, Zongxuan Sun, Suo Yang. Numerical Simulation of a Controlled Trajectory Rapid Compression Machine. AIAA Scitech 2020 Forum. 2020; ():1.

Chicago/Turabian Style

Krishna C. Bavandla; Dezhi Zhou; Abhinav Tripathi; Zongxuan Sun; Suo Yang. 2020. "Numerical Simulation of a Controlled Trajectory Rapid Compression Machine." AIAA Scitech 2020 Forum , no. : 1.

Conference paper
Published: 05 January 2020 in AIAA Scitech 2020 Forum
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The performance of both internal combustion engines and gas-turbines/aircraft-engines are highly sensitive to the characteristics of liquid fuel spray injection. To do a proper simulation of engine combustion, the first step is typically tuning the parameters of spray atomization breakup submodels for the specified conditions. However, properly tuning so many parameters wastes a lot of time for the engineers in both industry and academia. The present work uses a regularized multi-task neural nets to obtain the optimized parameters and quantifies the uncertainty of the suggested parameters. Reitz and Diwakar (RD) [1] and Reitz Kelvin-Helmholtz Rayleigh-Taylor (KH-RT) [2] are two widely used breakup models for high-pressure diesel-fuel spray. In this study, the Reitz KH-RT breakup model is taken into account. The neural network is trained by supervised learning approach, with discrepancy between simulation and experimental data as inputs and corresponding parameters as outputs. About 200 LES simulations of liquid fuel injection, which employ the Eulerian-Lagrangian approach, are conducted with different parameters to obtain the data for training. The input discrepancy is calculated based on both 1D data (penetration length) and 2D data (vapor boundary) from simulation and experimental data. The suggested parameters for the breakup submodel obtained from the neural network are evaluated. The discrepancy of suggested parameters is compared with neighbor training data. And the uncertainty quantification of model output is provided.

ACS Style

Hongyuan Zhang; Krishna C. Bavandla; Xiang Gao; Jianfeng Gao; Ping Yi; Suo Yang. Optimization and uncertainty quantification of spray break-up submodel with regularized multi-task neural nets. AIAA Scitech 2020 Forum 2020, 1 .

AMA Style

Hongyuan Zhang, Krishna C. Bavandla, Xiang Gao, Jianfeng Gao, Ping Yi, Suo Yang. Optimization and uncertainty quantification of spray break-up submodel with regularized multi-task neural nets. AIAA Scitech 2020 Forum. 2020; ():1.

Chicago/Turabian Style

Hongyuan Zhang; Krishna C. Bavandla; Xiang Gao; Jianfeng Gao; Ping Yi; Suo Yang. 2020. "Optimization and uncertainty quantification of spray break-up submodel with regularized multi-task neural nets." AIAA Scitech 2020 Forum , no. : 1.