J. V. R. Prasad

Prof. Dr. J. V. R. Prasad

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Academic Career Length

21Years (2006-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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22 October 2013 in Journal of Engineering for Gas Turbines and Power
Verified
Journal Article
Closed access
PDF file
GCGi-Yun Chung
Gi-Yun Chung
JPJ. V. R. Prasad
J. V. R. Prasad
MDManuj Dhingra
Manuj Dhingra
RMRichard Meisner
Richard Meisner
This paper presents a methodology for developing a control oriented analytical linear model of a turbofan engine at both equilibrium and nonequilibrium conditions. This scheme provides improved accuracy over the commonly used linearization method based on numerical perturbation and piecewise linear interpolation. Linear coefficients are obtained by evaluating at current conditions analytical expressions, which result from differentiation of simplified nonlinear expressions. Residualization of the fast dynamics states are utilized since the fast dynamics are outside of the primary control bandwidth. Analytical expressions based on the physics of the aerothermodynamic processes of a gas turbine engine facilitate a systematic approach to the analysis and synthesis of model based controllers. In addition, the use of analytical expressions reduces the computational effort, enabling linearization in real time at both equilibrium and nonequilibrium conditions to enable more accurate capture of system dynamics during aggressive transient maneuvers. The methodology is formulated and applied to a separate flow twin spool turbofan engine model in the numerical propulsion system simulation (NPSS) platform. The derived linear model is validated against the full nonlinear engine model.
1 January 2006
Verified
Conference Paper
Closed access
PDF file
MDManuj Dhingra
Manuj Dhingra
YNYedidia Neumeier
Yedidia Neumeier
JPJ. V. R. Prasad
J. V. R. Prasad
ABAndrew Breeze-Stringfellow
Andrew Breeze-Stringfellow
HSHyoun-Woo Shin
Hyoun-Woo Shin
PSPeter N. Szucs
Peter N. Szucs
A stability measure rooted in the unsteady characteristics of the flow field over the compressor rotor has been previously developed. The present work explores the relationship between the stochastic properties of this measure, called the correlation measure, and the compressor stability boundary. A stochastic model has been developed to gauge the impact of the correlation measure’s stochastic nature on its applicability to compressor stability management. The genesis of this model is in the fundamental properties of a specific stochastic process, one that is created by the threshold-crossings of a random process. The model validation utilizes data obtained on three different axial compressor facilities. These include a single stage low speed axial compressor, a four stage low speed research compressor and an advanced technology demonstrator high speed compressor. This paper presents details of the model development and validation, as well as, closed loop experimental results to demonstrate correlation measure’s usefulness in compressor stability management.
27 September 2013 in Journal of Intelligent & Robotic Systems
Verified
Journal Article
Closed access
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MZMin Zhou
Min Zhou
JPJ. V. R. Prasad
J. V. R. Prasad
1 July 2022 in Journal of Propulsion and Power
Verified
Journal Article
Closed access
YNYedidia Neumeier
Yedidia Neumeier
AMAbhishek Mishra
Abhishek Mishra
JPJ. V. R. Prasad
J. V. R. Prasad
DJDarrell K. James
Darrell K. James
In this paper, a model for simulating the intrinsic fast dynamics of flow in a multistage, axi-centrifugal compressor is presented. The model treats the flow through the stage elements, i.e., rotor...
26 January 2010 in Journal of Engineering for Gas Turbines and Power
Verified
Journal Article
Closed access
PDF file
MWMatthew A. White
Matthew A. White
MDManuj Dhingra
Manuj Dhingra
JPJ. V. R. Prasad
J. V. R. Prasad
An infinite-line probe is commonly used to measure unsteady pressure in high-temperature environments while protecting the pressure transducer. In this study, an existing theoretical model is used to derive the response of a waveguide pressure measuring system. An ambient temperature centrifugal compressor rig acts as an experimental source of fluctuating pressure. The compressor is operated at different discrete rotational speeds, and the blade-passing frequencies are used to obtain frequency response data. In the experiments, pressure waves attenuated at a rate faster than that predicted by the theoretical model for a 0.322 m (12 in.) sensor offset. Furthermore, the decay in the magnitude of the pressure oscillations accelerated at blade-passing frequencies above 9 kHz. A unique contribution of this study is to show that whereas the experimentally observed overall attenuation is broadly consistent with the theoretical predictions, pressure oscillations corresponding to individual blade passages may be disproportionally attenuated.
31 October 2024 in Aerospace
Verified
Journal Article
Open access
PDF file
MHMahmoud A Hayajnh
Mahmoud A Hayajnh
JPJ. V. R. Prasad
J. V. R. Prasad
This research paper investigates the applicability and scalability of the Rotor Control Equivalent Turbulence Input models for multi-rotor vehicles. Initially, a Rotor Control Equivalent Turbulence Input model is developed for an isolated rotor using rotor RPM as the input and the rotor hub-load coefficient as the output. Subsequently, the model is applied to multi-rotor vehicle example to show that the effect of turbulence on vehicle response can be replicated using the Rotor Control Equivalent Turbulence Input models. This study further incorporates rotor collective deflections, which could be used in multi-rotor vehicles, to develop a collective input model. Additionally, the effect of altering rotor parameters on the Rotor Control Equivalent Turbulence Input model is studied and presented. The results demonstrate that the Rotor Control Equivalent Turbulence Input model effectively captures the turbulence-induced behaviors in multi-rotor vehicles, offering a generalizable and scalable framework for use to replicate the effect of turbulence in multi-rotor vehicles.