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Research on the use of phase change material (PCM) suspensions to improve the natural convection efficiency of thermal systems is booming; however, there are few studies on the transient behavior of PCM suspensions. In this study, numerical simulations were used to investigate transient and steady-state natural convection in a square enclosure containing a PCM suspension. The implicit finite-difference method was adopted. The left and right walls of the enclosure were adiabatic sections, the bottom was an isothermal heating, and the top was an isothermal cooling. The following parameters were considered: PCM = n-octadecane (C18H38), enclosure aspect ratio= 1, buoyancy ratio for mass-to-heat transfer = 1, Rayleigh number (RaT) = 103-104, Stefan number (Ste) = 0.005-0.05, subcooling factor (Sb)= 0-10, and initial mass fraction (cm,i) = 0-20%. The results show that all the parameters (RaT, Ste, Sb, and cm,i) affect the flow pattern, and convection oscillations occur at Sb = 0.5-1. The heat transfer rate increases with RaT. Both cm,iand Sb affect the heat transfer rate but in a case-specific manner, and no well-defined correlations are observed.
C.J. Ho; C. Jang; Chi-Ming Lai. Natural convection heat transfer in PCM suspensions in a square enclosure with bottom heating and top cooling. Thermal Science and Engineering Progress 2021, 25, 101037 .
AMA StyleC.J. Ho, C. Jang, Chi-Ming Lai. Natural convection heat transfer in PCM suspensions in a square enclosure with bottom heating and top cooling. Thermal Science and Engineering Progress. 2021; 25 ():101037.
Chicago/Turabian StyleC.J. Ho; C. Jang; Chi-Ming Lai. 2021. "Natural convection heat transfer in PCM suspensions in a square enclosure with bottom heating and top cooling." Thermal Science and Engineering Progress 25, no. : 101037.
Research on using phase change material (PCM) suspension to improve the heat transfer and energy storage capabilities of thermal systems is booming; however, there are limited studies on the application of PCM suspension in transient natural convection. In this paper, the implicit finite difference method was used to numerically investigate the transient and steady-state natural convection heat transfer in a square enclosure containing a PCM suspension. The following parameters were included in the simulation: aspect ratio of the physical model = 1, ratio of the buoyancies caused by temperature and concentration gradients = 1, Raleigh number (
Ching-Jenq Ho; Chau-Yang Huang; Chi-Ming Lai. Heat Transfer by Natural Convection in a Square Enclosure Containing PCM Suspensions. Energies 2021, 14, 2857 .
AMA StyleChing-Jenq Ho, Chau-Yang Huang, Chi-Ming Lai. Heat Transfer by Natural Convection in a Square Enclosure Containing PCM Suspensions. Energies. 2021; 14 (10):2857.
Chicago/Turabian StyleChing-Jenq Ho; Chau-Yang Huang; Chi-Ming Lai. 2021. "Heat Transfer by Natural Convection in a Square Enclosure Containing PCM Suspensions." Energies 14, no. 10: 2857.
In this study, wind tunnel experiments and computational fluid dynamics (CFD) simulations were conducted to observe the channel airflow patterns and heat dissipation characteristics of dry storage casks for spent nuclear fuel. The parameter ranges were as follows: model scale = 1/10, Grashof number (Gr) = 1.0 × 1011, approaching wind angle (θ) = 0° or 45°, and Reynolds number (Re) = 2.6×104-8.0×105. The results show that a wind velocity = 3 m/s (Re = 8 × 104) is a critical condition for the channel airflow pattern inside the cask for cases in which θ = 0°. When θ = 45°, different wind velocities result in similar channel airflow patterns. As the wind velocity increases, the overall average surface temperature of the canister decreases, and the decrease lessens as the wind velocity increases.
Yao-Hung Wang; Yi-Pin Lin; Heui-Yung Chang; Chi-Ming Lai. Ventilation pattern and heat dissipation characteristics of a vertical dry storage cask for spent nuclear fuel: Wind tunnel experiments and CFD simulations. Annals of Nuclear Energy 2021, 160, 108364 .
AMA StyleYao-Hung Wang, Yi-Pin Lin, Heui-Yung Chang, Chi-Ming Lai. Ventilation pattern and heat dissipation characteristics of a vertical dry storage cask for spent nuclear fuel: Wind tunnel experiments and CFD simulations. Annals of Nuclear Energy. 2021; 160 ():108364.
Chicago/Turabian StyleYao-Hung Wang; Yi-Pin Lin; Heui-Yung Chang; Chi-Ming Lai. 2021. "Ventilation pattern and heat dissipation characteristics of a vertical dry storage cask for spent nuclear fuel: Wind tunnel experiments and CFD simulations." Annals of Nuclear Energy 160, no. : 108364.
Computational fluid dynamics (CFD) was used in this study to numerically simulate the heat removal and hybrid ventilation characteristics of a vertical dry storage cask for spent nuclear fuel. The parameters included a Grashof number of 1.0x1011, an approaching wind incidence angle of 0° or 45°, and a Reynolds number (Re) of 2.7×104-8.0×105 (Gr/Re2=0.15-137). As shown by the results, the buoyant airflow dominated the heat removal capability of the cask at low Re (2.7×104). When the Re was increased to 5.3×104-1.3×105, the wind-induced channel airflow compromised the buoyant airflow, thus reducing the heat removal capacity of the cask. When the Re was⩾2.7×105, the wind-induced airflow dominated.
Yao-Hung Wang; Kuo-Cheng Yen; Heui-Yung Chang; Chi-Ming Lai. Heat removal and hybrid ventilation characteristics of a vertical dry storage cask for spent nuclear fuel. Nuclear Engineering and Design 2021, 378, 111183 .
AMA StyleYao-Hung Wang, Kuo-Cheng Yen, Heui-Yung Chang, Chi-Ming Lai. Heat removal and hybrid ventilation characteristics of a vertical dry storage cask for spent nuclear fuel. Nuclear Engineering and Design. 2021; 378 ():111183.
Chicago/Turabian StyleYao-Hung Wang; Kuo-Cheng Yen; Heui-Yung Chang; Chi-Ming Lai. 2021. "Heat removal and hybrid ventilation characteristics of a vertical dry storage cask for spent nuclear fuel." Nuclear Engineering and Design 378, no. : 111183.
This study explores the effects of pipe wall properties (thermal conductivity k and wall thickness tw) on the heat transfer performance of a rectangular thermosyphon with a phase change material (PCM) suspension and a geometric configuration (aspect ratio = 1; dimensionless heating section length = 0.8; dimensionless relative elevation between the cooling and the heating sections = 2) that ensures the optimum heat transfer efficiency in the cooling section. The following parameter ranges are studied: the dimensionless loop wall thickness (0 to 0.5), wall-to-fluid thermal conductivity ratio (0.1 to 100), modified Rayleigh number (1010 to 1011), and volumetric fraction of PCM particles (0 to 10%). The results show that appropriate selection of k and tw can lead to improved heat transfer effectiveness in the cooling section of the PCM suspension-containing rectangular thermosyphon.
Ching-Jenq Ho; Shih-Ming Lin; Chi-Ming Lai. Effects of the Wall Properties on the Cooling Efficiency in a Thermosyphon Containing PCM Suspensions. Energies 2021, 14, 572 .
AMA StyleChing-Jenq Ho, Shih-Ming Lin, Chi-Ming Lai. Effects of the Wall Properties on the Cooling Efficiency in a Thermosyphon Containing PCM Suspensions. Energies. 2021; 14 (3):572.
Chicago/Turabian StyleChing-Jenq Ho; Shih-Ming Lin; Chi-Ming Lai. 2021. "Effects of the Wall Properties on the Cooling Efficiency in a Thermosyphon Containing PCM Suspensions." Energies 14, no. 3: 572.
This article considers the problem of natural heat transfer in a rectangular thermosiphon to investigate the effects of wall properties (thickness and thermal conductivity) on the heat-transfer characteristics of phase-change-material (PCM) suspension flow. The following parameter ranges were investigated: dimensionless loop-wall thickness, 0–0.5; wall-to-fluid thermal-conductivity ratio, 0.1–100; modified Rayleigh number, 1010–1011; and volumetric fraction of PCM particles, 0–10%. From numerical simulations via the finite-volume approach, it was found that using a pipe with appropriate wall thickness and thermal conductivity containing PCM suspensions for the heating section of a rectangular thermosiphon can effectively control the maximal temperature.
Ching-Jenq Ho; Shih-Ming Lin; Rong-Horng Chen; Chi-Ming Lai. Effects of Wall Properties on Temperature-Control Effectiveness of Heating Section in a Thermosiphon Containing PCM Suspensions. Applied Sciences 2020, 10, 6211 .
AMA StyleChing-Jenq Ho, Shih-Ming Lin, Rong-Horng Chen, Chi-Ming Lai. Effects of Wall Properties on Temperature-Control Effectiveness of Heating Section in a Thermosiphon Containing PCM Suspensions. Applied Sciences. 2020; 10 (18):6211.
Chicago/Turabian StyleChing-Jenq Ho; Shih-Ming Lin; Rong-Horng Chen; Chi-Ming Lai. 2020. "Effects of Wall Properties on Temperature-Control Effectiveness of Heating Section in a Thermosiphon Containing PCM Suspensions." Applied Sciences 10, no. 18: 6211.
In this paper, a numerical method was used to investigate the conjugate heat transfer of phase change material (PCM) suspensions in a circular pipe under external cooling convection. The parameters considered in this study and their ranges were the volumetric fraction of PCM particles (cv) = 0–0.2, the Biot number (Bio) = 0.1–100, the Stefan number (Ste) = 0.01–0.2, and the Peclet number (Pe) = 100–1000. The results showed that the PCM concentration, Bio, and Ste had significant effects on the fluid temperature, inner/outer wall temperature, and inner/outer wall heat flux, while Pe only had a significant effect on the axial heat transfer of the wall. When a PCM-containing working fluid was used for cooling, the PCM latent heat could directly affect the fluid outlet temperature and the cooling effect. If the latent heat is changed, other thermal system parameters should be adjusted accordingly.
C.J. Ho; Z.C. Wang; R.H. Chen; Chi-Ming Lai. Conjugate heat transfer analysis of PCM suspensions in a circular pipe subjected to external cooling convection: Parameter effects. International Journal of Heat and Mass Transfer 2020, 162, 120369 .
AMA StyleC.J. Ho, Z.C. Wang, R.H. Chen, Chi-Ming Lai. Conjugate heat transfer analysis of PCM suspensions in a circular pipe subjected to external cooling convection: Parameter effects. International Journal of Heat and Mass Transfer. 2020; 162 ():120369.
Chicago/Turabian StyleC.J. Ho; Z.C. Wang; R.H. Chen; Chi-Ming Lai. 2020. "Conjugate heat transfer analysis of PCM suspensions in a circular pipe subjected to external cooling convection: Parameter effects." International Journal of Heat and Mass Transfer 162, no. : 120369.
We are investigating how to use urban design approaches to conduct the layout and basic design of newly-built high-rise buildings to reduce wind obstruction and create effective urban ventilation. Few studies have addressed this issue. This study analyzes the effects of high-rise building on pedestrian-level wind in downstream street canyons based on wind tunnel test results, and examines the suitability of an urban design specification. The height (H) of high-rise buildings and the airflow passage width (S) between adjacent high-rise buildings are key control factors for this issue; H/D = 3 and S/D = 1.125 are critical parameters and recommended values (D is the height of the downstream street blocks).
Chien-Yuan Kuo; Rong-Jing Wang; Yi-Pin Lin; Chi-Ming Lai. Urban Design with the Wind: Pedestrian-Level Wind Field in the Street Canyons Downstream of Parallel High-Rise Buildings. Energies 2020, 13, 2827 .
AMA StyleChien-Yuan Kuo, Rong-Jing Wang, Yi-Pin Lin, Chi-Ming Lai. Urban Design with the Wind: Pedestrian-Level Wind Field in the Street Canyons Downstream of Parallel High-Rise Buildings. Energies. 2020; 13 (11):2827.
Chicago/Turabian StyleChien-Yuan Kuo; Rong-Jing Wang; Yi-Pin Lin; Chi-Ming Lai. 2020. "Urban Design with the Wind: Pedestrian-Level Wind Field in the Street Canyons Downstream of Parallel High-Rise Buildings." Energies 13, no. 11: 2827.
The pedestrian wind environment in a street canyon is affected by a multitude of factors, including the height and geometric shape of the surrounding buildings, the street width, the wind direction, and speed. Wind-tunnel tests were performed to determine the effects of constructing high buildings in an urban renewal project in New Taipei City, Taiwan on the pedestrian wind environments in the surrounding street canyons. The results show that replacing the original low-rise buildings with high-rise buildings could decrease the wind speed and natural ventilation potential in certain surrounding street canyons. The flow fields generated by approaching winds in various street canyons are highly complex in this practical case study. Thus, the pedestrian wind patterns in the street canyons cannot be interpreted in terms of channeling and shielding effects alone, as is typically reported in the literature.
Tzu-Ling Huang; Chien-Yuan Kuo; Chun-Ta Tzeng; Chi-Ming Lai. The Influence of High-Rise Buildings on Pedestrian-Level Wind in Surrounding Street Canyons in an Urban Renewal Project. Energies 2020, 13, 2745 .
AMA StyleTzu-Ling Huang, Chien-Yuan Kuo, Chun-Ta Tzeng, Chi-Ming Lai. The Influence of High-Rise Buildings on Pedestrian-Level Wind in Surrounding Street Canyons in an Urban Renewal Project. Energies. 2020; 13 (11):2745.
Chicago/Turabian StyleTzu-Ling Huang; Chien-Yuan Kuo; Chun-Ta Tzeng; Chi-Ming Lai. 2020. "The Influence of High-Rise Buildings on Pedestrian-Level Wind in Surrounding Street Canyons in an Urban Renewal Project." Energies 13, no. 11: 2745.
A numerical and experimental study is presented to explore the effects of cooling (the section on subcooling and phase-change material (PCM) supercooling) on the thermal performance of a rectangular thermosyphon containing PCM suspensions. In the numerical simulation, a continuum mixture flow model is used for the buoyancy-driven circulation flow of the PCM suspensions together with an approximate enthalpy model to detail the solid-liquid phase change process of the PCM particles in the loop. Parametric simulations are conducted in the following ranges: heat input at the heating section = 12 W, average temperature of the outer wall of the cooling section = 10–25 °C, and PCM mass concentration = 0–15%. The results show that in the configuration of this study, the downward flow of the high-density fluid in the cooling section became the main driving force of the circulation loop. Therefore, the cooling effects affected the overall thermal performance. To allow the proper melting/freezing of PCM particles, it is critical to control the wall temperature at the cooling section to achieve an appropriate subcooling effect.
C.J. Ho; J.F. Lin; R.H. Chen; Chi-Ming Lai. Cooling effects on the heat transfer characteristics of a rectangular thermosyphon with PCM suspension fluid. International Journal of Heat and Mass Transfer 2020, 157, 119955 .
AMA StyleC.J. Ho, J.F. Lin, R.H. Chen, Chi-Ming Lai. Cooling effects on the heat transfer characteristics of a rectangular thermosyphon with PCM suspension fluid. International Journal of Heat and Mass Transfer. 2020; 157 ():119955.
Chicago/Turabian StyleC.J. Ho; J.F. Lin; R.H. Chen; Chi-Ming Lai. 2020. "Cooling effects on the heat transfer characteristics of a rectangular thermosyphon with PCM suspension fluid." International Journal of Heat and Mass Transfer 157, no. : 119955.
In this study, we considered different the wind speeds affects the thermal performance when the dry storage cask for spent nuclear fuel , which used NAC- MAGNASTOR cask of system, and placed outdoors. We Ddiscuss the dry storage cask for spent nuclear fuel cooling by the thermal buoyancy ventilation of cask. Firstly, Compare the experimental data of low-speed wind tunnel experiments with the result of from a commercial software PHOENICS CFD (Computational Fluid Dynamics) for heat flow analysis, and confirm the reliability of the CFD simulation results of the software. Then we used the software to simulate higher wind speeds to understand the thermal performance of the cask for spent nuclear fuel by various wind speeds. With external wind speed is was more much faster, channel airflow of the cask hads increased, especially upper channel airflow of the cask and near steel cylindrical. The temperature of the windward side of the cask hads also been significantly reduced, The lee side hads a slower wind speed and a smaller temperature drop, and generates an eddy below the lee side, which helpeds to dissipate .heat,. However, as the wind speed gradually increases, the lee side changed to a downdraft, and the temperature drop was also slowed down. It is noticeable that the situation may occur when a typhoon comes.
Linying Cheng; Chi-Ming Lai. The effect of the cooling on a dry storage cask for spent nuclear fuel by different wind speed. 2020, 1 .
AMA StyleLinying Cheng, Chi-Ming Lai. The effect of the cooling on a dry storage cask for spent nuclear fuel by different wind speed. . 2020; ():1.
Chicago/Turabian StyleLinying Cheng; Chi-Ming Lai. 2020. "The effect of the cooling on a dry storage cask for spent nuclear fuel by different wind speed." , no. : 1.
In this paper, a numerical method is used to investigate the conjugate heat transfer of a phase change material (PCM) suspension in a circular tube under external cooling convection. The following parameters and ranges were considered: dimensionless tube wall thickness, t w (0–0.5); wall-to-fluid thermal conductivity ratio, k w f * (0.1–10); volumetric fraction of PCM particles, c v (0.1); Biot number, B i o (1); Stefan number, Ste (0.1); and Peclet number, Pe (1000). The results show that the wall thermal conductivity considerably affects the outer/inner wall temperature of the tube, the average temperature of the working fluid, and the volumetric liquid fraction of PCM particles. Thus, wall conduction effects must be properly accounted for to model heat transfer in a PCM suspension in tube flow.
C. J. Ho; Z.C. Wang; R.H. Chen; Chi-Ming Lai. Conjugate Heat Transfer Analysis of PCM Suspensions in a Circular Tube under External Cooling Convection: Wall Conduction Effects. Applied Sciences 2020, 10, 2034 .
AMA StyleC. J. Ho, Z.C. Wang, R.H. Chen, Chi-Ming Lai. Conjugate Heat Transfer Analysis of PCM Suspensions in a Circular Tube under External Cooling Convection: Wall Conduction Effects. Applied Sciences. 2020; 10 (6):2034.
Chicago/Turabian StyleC. J. Ho; Z.C. Wang; R.H. Chen; Chi-Ming Lai. 2020. "Conjugate Heat Transfer Analysis of PCM Suspensions in a Circular Tube under External Cooling Convection: Wall Conduction Effects." Applied Sciences 10, no. 6: 2034.
The natural convection behaviors of rectangular thermosyphons with different aspect ratios were experimentally analyzed in this study. The experimental model consisted of a loop body, a heating section, a cooling section, and adiabatic sections. The heating and cooling sections were located in the vertical portions of the rectangular loop. The length of the vertical cooling section and the lengths of the upper and lower adiabatic sections were fixed at 300 mm and 200 mm, respectively. The inner diameter of the loop was fixed at 11 mm, and the cooling end temperature was 30 °C. The relevant parameters and their ranges were as follows: The aspect ratios were 6, 4.5, and 3.5 (with potential differences of 41, 27, and 18, respectively, between the cold and hot ends), and the input thermal power ranged from 30 to 60 W (with a heat flux of 600 to 3800 W/m2). The results show that it is feasible to obtain solar heat gain by installing a rectangular thermosyphon inside the metal curtain wall and that increasing the height of the opaque part of the metal curtain wall can increase the aspect ratio of the rectangular thermosyphon installed inside the wall and thus improve the heat transfer efficiency.
Chia-Wang Yu; C. S. Huang; C. T. Tzeng; Chi-Ming Lai. Effects of the Aspect Ratio of a Rectangular Thermosyphon on Its Thermal Performance. Energies 2019, 12, 4014 .
AMA StyleChia-Wang Yu, C. S. Huang, C. T. Tzeng, Chi-Ming Lai. Effects of the Aspect Ratio of a Rectangular Thermosyphon on Its Thermal Performance. Energies. 2019; 12 (20):4014.
Chicago/Turabian StyleChia-Wang Yu; C. S. Huang; C. T. Tzeng; Chi-Ming Lai. 2019. "Effects of the Aspect Ratio of a Rectangular Thermosyphon on Its Thermal Performance." Energies 12, no. 20: 4014.
Using computational fluid dynamics (CFD), this study explores the effect of a different number of awning windows and their installation locations on the airflow patterns and air contaminant distributions in restrooms in K-12 (for kindergarten to 12th grade) public schools in Taiwan. A representative restroom configuration with dimensions of 10.65 m × 9.2 m × 3.2 m (height) was selected as the investigated object. Based on the façade design feasibility, seven possible awning window configurations were considered. The results indicate that an adequate number of windows and appropriate installation locations are required to ensure the natural ventilation effectiveness of awning windows. The recommended installation configuration is provided.
Sung-Chin Chung; Yi-Pin Lin; Chun Yang; Chi-Ming Lai. Natural Ventilation Effectiveness of Awning Windows in Restrooms in K-12 Public Schools. Energies 2019, 12, 2414 .
AMA StyleSung-Chin Chung, Yi-Pin Lin, Chun Yang, Chi-Ming Lai. Natural Ventilation Effectiveness of Awning Windows in Restrooms in K-12 Public Schools. Energies. 2019; 12 (12):2414.
Chicago/Turabian StyleSung-Chin Chung; Yi-Pin Lin; Chun Yang; Chi-Ming Lai. 2019. "Natural Ventilation Effectiveness of Awning Windows in Restrooms in K-12 Public Schools." Energies 12, no. 12: 2414.
In this study, a heat management module containing a microencapsulated phase change material (mPCM) was fabricated from mPCM (core material: paraffin; melting temperature: 37 °C) and aluminum honeycomb structures (8 mm core cell). The aluminum honeycomb functioned both as structural support and as a heat transfer channel. The thermal management performance of the proposed module under constant-temperature boundary conditions was investigated experimentally. The thermal protection period of the module decreased as the Stefan number increased; however, increasing the subcooling factor could effectively enhance the thermal protection performance. When the cold-wall temperature TC was fixed at 17 °C and the initial hot wall temperature was 47–67 °C, the heat dissipation of the module was complete 140 min after the hot-wall heat supply was stopped. The time required to complete the heat dissipation increased to 280 min when TC increased to 27 °C.
H.M. Shih; Yi-Pin Lin; L.P. Lin; Chi-Ming Lai. Thermal Characterization of a Heat Management Module Containing Microencapsulated Phase Change Material. Energies 2019, 12, 2164 .
AMA StyleH.M. Shih, Yi-Pin Lin, L.P. Lin, Chi-Ming Lai. Thermal Characterization of a Heat Management Module Containing Microencapsulated Phase Change Material. Energies. 2019; 12 (11):2164.
Chicago/Turabian StyleH.M. Shih; Yi-Pin Lin; L.P. Lin; Chi-Ming Lai. 2019. "Thermal Characterization of a Heat Management Module Containing Microencapsulated Phase Change Material." Energies 12, no. 11: 2164.
This study experimentally investigates the natural convection heat transfer performance of a rectangular thermosyphon with an aspect ratio of 3.5. The experimental model is divided into a loop body, a heating section, a cooling section, and two adiabatic sections. The heating section and the cooling section are located in the vertical legs of the rectangular loop. The length of the vertical heating section and the length of the upper and lower horizontal insulation sections are 700 mm and 200 mm, respectively, and the inner diameter of the loop is 11 mm. The relevant parameters and their ranges are as follows: the input thermal power is 30–60 W (with a heat flux in the range of 60–3800 W/m2); the temperature in the cooling section is 30, 40, or 50 °C; and the potential difference between the hot and cold sections is 5, 11, or 18 for the cooling section lengths of 60, 45, and 30 cm, respectively. The results indicate that the value of the dimensionless heat transfer coefficient, the Nusselt number, is generally between 5 and 10. The heating power is the main factor affecting the natural convection intensity of the thermosyphon.
C. S. Huang; Chia-Wang Yu; R. H. Chen; Chun-Ta Tzeng; Chi-Ming Lai. Experimental Observation of Natural Convection Heat Transfer Performance of a Rectangular Thermosyphon. Energies 2019, 12, 1702 .
AMA StyleC. S. Huang, Chia-Wang Yu, R. H. Chen, Chun-Ta Tzeng, Chi-Ming Lai. Experimental Observation of Natural Convection Heat Transfer Performance of a Rectangular Thermosyphon. Energies. 2019; 12 (9):1702.
Chicago/Turabian StyleC. S. Huang; Chia-Wang Yu; R. H. Chen; Chun-Ta Tzeng; Chi-Ming Lai. 2019. "Experimental Observation of Natural Convection Heat Transfer Performance of a Rectangular Thermosyphon." Energies 12, no. 9: 1702.
In this study, a numerical simulation of natural convection between two horizontal differentially heated pipelines inside a circular air-filled enclosure is performed using the finite difference method. The relevant parameters of the problem are the inclinations of the two cylinders (positioned vertically in this study, with the cold cylinder above the hot cylinder), the distance between cylinders and the Rayleigh number. The results show that transient irregular fluctuations in the flow field and heat transfer occur when the Rayleigh number increases or the distance between cylinders decreases. Under the current test conditions, increasing the Rayleigh number significantly increases the average heat transfer coefficient between the cold and hot cylinders.
C.J. Ho; G.N. Sou; Chi-Ming Lai. Transient Heat Transfer Between Two Horizontal Pipelines in a Heat Tracing Enclosure. Energies 2019, 12, 1440 .
AMA StyleC.J. Ho, G.N. Sou, Chi-Ming Lai. Transient Heat Transfer Between Two Horizontal Pipelines in a Heat Tracing Enclosure. Energies. 2019; 12 (8):1440.
Chicago/Turabian StyleC.J. Ho; G.N. Sou; Chi-Ming Lai. 2019. "Transient Heat Transfer Between Two Horizontal Pipelines in a Heat Tracing Enclosure." Energies 12, no. 8: 1440.
This study investigated the movable fire loads and the characteristics of combustible materials in Japanese-style wooden historical buildings via field surveys and cone calorimeter experiments. Twenty-one historical buildings with 102 rooms and a total floor area of 2235.06 m2 were surveyed to determine the movable fire load. Strong correlations among fire load density, compartment floor area, and spatial use are found in this survey. The mean values of the movable fire load density in decreasing order in terms of room use are storeroom (431.38 MJ/m2), study room (298 MJ/m2), bedroom (294.88 MJ/m2), reception room (287.20 MJ/m2), and dining room (217.11 MJ/m2), providing fire engineering design with a reliable fire load setting in various types of rooms in historical buildings.
Hung-Chi Su; Shu-Fen Tung; Chun-Ta Tzeng; Chi-Ming Lai. Survey and Experimental Investigation of Movable Fire Loads in Japanese-Style Wooden Historical Buildings. International Journal of Architectural Heritage 2019, 14, 931 -942.
AMA StyleHung-Chi Su, Shu-Fen Tung, Chun-Ta Tzeng, Chi-Ming Lai. Survey and Experimental Investigation of Movable Fire Loads in Japanese-Style Wooden Historical Buildings. International Journal of Architectural Heritage. 2019; 14 (6):931-942.
Chicago/Turabian StyleHung-Chi Su; Shu-Fen Tung; Chun-Ta Tzeng; Chi-Ming Lai. 2019. "Survey and Experimental Investigation of Movable Fire Loads in Japanese-Style Wooden Historical Buildings." International Journal of Architectural Heritage 14, no. 6: 931-942.
Fire safety is an important issue in all types of construction, especially in wooden-frame historical buildings. In this study, room fire experiments were conducted in a full-scale model storeroom with high fire load in a wooden historical building to explore fire growth and spread via heat release rates and indoor air temperatures. Numerical simulations mimicking the fire scenario were conducted using FDS software to predict fire features, and these findings were compared with the experimental results. The results showed that development trends during fire growth were aligned, but they displayed time differences. During the fully developed fire period, the heat release rates from the experiment were less than the predicted values. The reason for the low heat release rates in the experiment was that the collapse and stacking of fire loads were not effectively simulated.
Shu-Fen Tung; Hung-Chi Su; Chun-Ta Tzeng; Chi-Ming Lai. Experimental and Numerical Investigation of a Room Fire in a Wooden-Frame Historical Building. International Journal of Architectural Heritage 2018, 14, 106 -118.
AMA StyleShu-Fen Tung, Hung-Chi Su, Chun-Ta Tzeng, Chi-Ming Lai. Experimental and Numerical Investigation of a Room Fire in a Wooden-Frame Historical Building. International Journal of Architectural Heritage. 2018; 14 (1):106-118.
Chicago/Turabian StyleShu-Fen Tung; Hung-Chi Su; Chun-Ta Tzeng; Chi-Ming Lai. 2018. "Experimental and Numerical Investigation of a Room Fire in a Wooden-Frame Historical Building." International Journal of Architectural Heritage 14, no. 1: 106-118.
This study explores the effect of different numbers of wall-mounted vent caps and their installation locations on the indoor air environment in residential kitchens, for which limited information is available. Wind tunnel tests were performed to study the induced ventilation rates of a vent cap, and the impact of vent caps on the natural ventilation efficiency in residential kitchens was examined using computational fluid dynamics (CFD) numerical simulations. The results were then applied to determine the appropriate quantity of vent caps and their proper installation location. The wind tunnel test results indicated that outdoor winds with speeds of 0–6 m/s that flow parallel to the wall with a vent cap induce indoor air to exit through the cap with ventilation rates of 0–20 m3/h; when the wind blows perpendicular to the wall, outdoor air with 0–31.9 m3/h flows indoors. CFD numerical simulations showed that the installation of kitchen vent caps can reduce the average carbon monoxide concentration in the cook’s breathing zone. A sufficient quantity of vent caps and the proper installation location are required to ensure the natural ventilation effectiveness of wall-mounted vent caps.
Yi-Pin Lin; Chiemi Iba; Chi-Ming Lai. Natural Ventilation Effectiveness of Round Wall-Mounted Vent Caps in Residential Kitchens. Energies 2018, 11, 1230 .
AMA StyleYi-Pin Lin, Chiemi Iba, Chi-Ming Lai. Natural Ventilation Effectiveness of Round Wall-Mounted Vent Caps in Residential Kitchens. Energies. 2018; 11 (5):1230.
Chicago/Turabian StyleYi-Pin Lin; Chiemi Iba; Chi-Ming Lai. 2018. "Natural Ventilation Effectiveness of Round Wall-Mounted Vent Caps in Residential Kitchens." Energies 11, no. 5: 1230.