Centrifugal compressor study in mini-jet engine

Mini-turbojet engines, with their advantages of small size and less weight, are widely used in the unmanned area vehicles. One of the most significant parts – the mini centrifugal compressor is investigated in this study. In order to optimize the pressure ratio and efficiency of a mini centrifugal c...

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Main Author: Guo, Shuai.
Other Authors: School of Mechanical and Aerospace Engineering
Format: Theses and Dissertations
Language:English
Published: 2013
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Online Access:http://hdl.handle.net/10356/54696
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-546962023-03-11T17:31:06Z Centrifugal compressor study in mini-jet engine Guo, Shuai. School of Mechanical and Aerospace Engineering Fei Duan, Hui Tang DRNTU::Engineering::Aeronautical engineering::Aircraft motors and engines Mini-turbojet engines, with their advantages of small size and less weight, are widely used in the unmanned area vehicles. One of the most significant parts – the mini centrifugal compressor is investigated in this study. In order to optimize the pressure ratio and efficiency of a mini centrifugal compressor, the design of experiments (DOE) technique and computational fluid dynamics (CFD) are used in this study. A numerical model is built using Axcent® software to study the compressor performance. The grid independence and near wall mesh sensitivity studies are conducted using Spalart-Allmaras (S-A) turbulence model with the pbCFD® solver. The appropriate model is recommended with 214,389 grid nodes, and the y+ value is between 20~100. The experiments of the SR-30 mini turbojet engine are conducted at 4 different rotating speeds: 50,000 RPM; 60,000 RPM; 70,000 RPM and 80,000 RPM. All the data are collected under steady state. The validation of simulation results with the experimental data shows less than 4% difference on the pressure ratio. Based on the numerical method, the compressor performance map of the SR-30 mini turbojet engine is given. Together with the flow distribution at the impeller inlet, the compressor surge and choke studies are conducted to predict the operating range. The first design investigates three compressor parameters from geometrical analysis. Both the first-order and the second-order regression model are used to optimize the original compressor. The first design shows 4.54% increase in isentropic efficiency and 15.85% increase in pressure ratio. The second design is conducted separately of impeller and diffuser. The screen analysis is used to select six parameters for impeller and four parameters for diffuser. Both the Pareto front solutions and the weighted metric method are used to find out the optimal solutions from the compressors. The second design shows 5.63% increase in efficiency and 21.89% increase in pressure ratio. The third design is a totally new design from a meanline analysis software – Compal. Based on the size limitation for the mini-jet engine, the third design is generated with 10.5 mm hub radius impeller and 10 blades diffuser under two commercial optimization softwares, TurboOpt II and IOSO. The third design shows 2.99 in pressure ratio (12.8% increase than the original one) and 77.77 % in isentropic efficiency (10.9% increase than the original one). After all the designs are finished, we are fabricating the optimized compressors and testing the new engine. The testing is on-going and the results will be shown in the future work. Master of Engineering (MAE) 2013-07-23T08:12:13Z 2013-07-23T08:12:13Z 2013 2013 Thesis http://hdl.handle.net/10356/54696 en 191 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Engineering::Aeronautical engineering::Aircraft motors and engines
spellingShingle DRNTU::Engineering::Aeronautical engineering::Aircraft motors and engines
Guo, Shuai.
Centrifugal compressor study in mini-jet engine
description Mini-turbojet engines, with their advantages of small size and less weight, are widely used in the unmanned area vehicles. One of the most significant parts – the mini centrifugal compressor is investigated in this study. In order to optimize the pressure ratio and efficiency of a mini centrifugal compressor, the design of experiments (DOE) technique and computational fluid dynamics (CFD) are used in this study. A numerical model is built using Axcent® software to study the compressor performance. The grid independence and near wall mesh sensitivity studies are conducted using Spalart-Allmaras (S-A) turbulence model with the pbCFD® solver. The appropriate model is recommended with 214,389 grid nodes, and the y+ value is between 20~100. The experiments of the SR-30 mini turbojet engine are conducted at 4 different rotating speeds: 50,000 RPM; 60,000 RPM; 70,000 RPM and 80,000 RPM. All the data are collected under steady state. The validation of simulation results with the experimental data shows less than 4% difference on the pressure ratio. Based on the numerical method, the compressor performance map of the SR-30 mini turbojet engine is given. Together with the flow distribution at the impeller inlet, the compressor surge and choke studies are conducted to predict the operating range. The first design investigates three compressor parameters from geometrical analysis. Both the first-order and the second-order regression model are used to optimize the original compressor. The first design shows 4.54% increase in isentropic efficiency and 15.85% increase in pressure ratio. The second design is conducted separately of impeller and diffuser. The screen analysis is used to select six parameters for impeller and four parameters for diffuser. Both the Pareto front solutions and the weighted metric method are used to find out the optimal solutions from the compressors. The second design shows 5.63% increase in efficiency and 21.89% increase in pressure ratio. The third design is a totally new design from a meanline analysis software – Compal. Based on the size limitation for the mini-jet engine, the third design is generated with 10.5 mm hub radius impeller and 10 blades diffuser under two commercial optimization softwares, TurboOpt II and IOSO. The third design shows 2.99 in pressure ratio (12.8% increase than the original one) and 77.77 % in isentropic efficiency (10.9% increase than the original one). After all the designs are finished, we are fabricating the optimized compressors and testing the new engine. The testing is on-going and the results will be shown in the future work.
author2 School of Mechanical and Aerospace Engineering
author_facet School of Mechanical and Aerospace Engineering
Guo, Shuai.
format Theses and Dissertations
author Guo, Shuai.
author_sort Guo, Shuai.
title Centrifugal compressor study in mini-jet engine
title_short Centrifugal compressor study in mini-jet engine
title_full Centrifugal compressor study in mini-jet engine
title_fullStr Centrifugal compressor study in mini-jet engine
title_full_unstemmed Centrifugal compressor study in mini-jet engine
title_sort centrifugal compressor study in mini-jet engine
publishDate 2013
url http://hdl.handle.net/10356/54696
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