Parametric investigation on the essential flow factors commanding steady operations of the second throat exhaust diffuser

Jihwan Lim, Byung Hoon Park, Woongsup Yoon, Yeol Lee

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Citations (Scopus)

Abstract

The constant area exhaust diffuser (CAED) demands a higher starting pressure than the second throat exhaust diffuser (STED). In the design process, one dimensional (1D) normal shock theory was explored to obtain the optimum starting pressure of STED. Experiments were conducted with a small scale cold gas simulator using nitrogen gas as injectant. The application of 1D normal shock theory for STED design was examined with 20-25% difference in each accuracy in comparison to numerical and experimental evidences. The relation between evacuation quality and essential geometrical parameters such as diffuser-to-nozzle throat area ratio (Ad/At), diffuser-to-the second throat area ratio (Ad/As), and the nozzle expansion ratio (ε) is presented for the optimization of STED. The optimum starting pressure increases in proportion to Ad/At and the optimized Ad/As was predicted in the range of 2.2-2.5. After STED starting, the evacuation quality is the same whether the expansion ratio of the nozzle is large or not. However, the range of the transition regime varied according to the nozzle expansion ratio.

Original languageEnglish
Title of host publication44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit
Publication statusPublished - 2008 Dec 1
Event44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit - Hartford, CT, United States
Duration: 2008 Jul 212008 Jul 23

Publication series

Name44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit

Other

Other44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit
CountryUnited States
CityHartford, CT
Period08/7/2108/7/23

Fingerprint

exhaust diffusers
throats
Nozzles
nozzles
gas
simulator
diffusers
nitrogen
expansion
Gases
shock
experiment
Simulators
Nitrogen
cold gas
simulators
proportion

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering
  • Control and Systems Engineering
  • Space and Planetary Science
  • Energy(all)
  • Electrical and Electronic Engineering
  • Mechanical Engineering

Cite this

Lim, J., Park, B. H., Yoon, W., & Lee, Y. (2008). Parametric investigation on the essential flow factors commanding steady operations of the second throat exhaust diffuser. In 44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit (44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit).
Lim, Jihwan ; Park, Byung Hoon ; Yoon, Woongsup ; Lee, Yeol. / Parametric investigation on the essential flow factors commanding steady operations of the second throat exhaust diffuser. 44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit. 2008. (44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit).
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abstract = "The constant area exhaust diffuser (CAED) demands a higher starting pressure than the second throat exhaust diffuser (STED). In the design process, one dimensional (1D) normal shock theory was explored to obtain the optimum starting pressure of STED. Experiments were conducted with a small scale cold gas simulator using nitrogen gas as injectant. The application of 1D normal shock theory for STED design was examined with 20-25{\%} difference in each accuracy in comparison to numerical and experimental evidences. The relation between evacuation quality and essential geometrical parameters such as diffuser-to-nozzle throat area ratio (Ad/At), diffuser-to-the second throat area ratio (Ad/As), and the nozzle expansion ratio (ε) is presented for the optimization of STED. The optimum starting pressure increases in proportion to Ad/At and the optimized Ad/As was predicted in the range of 2.2-2.5. After STED starting, the evacuation quality is the same whether the expansion ratio of the nozzle is large or not. However, the range of the transition regime varied according to the nozzle expansion ratio.",
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Lim, J, Park, BH, Yoon, W & Lee, Y 2008, Parametric investigation on the essential flow factors commanding steady operations of the second throat exhaust diffuser. in 44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit. 44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, Hartford, CT, United States, 08/7/21.

Parametric investigation on the essential flow factors commanding steady operations of the second throat exhaust diffuser. / Lim, Jihwan; Park, Byung Hoon; Yoon, Woongsup; Lee, Yeol.

44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit. 2008. (44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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N2 - The constant area exhaust diffuser (CAED) demands a higher starting pressure than the second throat exhaust diffuser (STED). In the design process, one dimensional (1D) normal shock theory was explored to obtain the optimum starting pressure of STED. Experiments were conducted with a small scale cold gas simulator using nitrogen gas as injectant. The application of 1D normal shock theory for STED design was examined with 20-25% difference in each accuracy in comparison to numerical and experimental evidences. The relation between evacuation quality and essential geometrical parameters such as diffuser-to-nozzle throat area ratio (Ad/At), diffuser-to-the second throat area ratio (Ad/As), and the nozzle expansion ratio (ε) is presented for the optimization of STED. The optimum starting pressure increases in proportion to Ad/At and the optimized Ad/As was predicted in the range of 2.2-2.5. After STED starting, the evacuation quality is the same whether the expansion ratio of the nozzle is large or not. However, the range of the transition regime varied according to the nozzle expansion ratio.

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Lim J, Park BH, Yoon W, Lee Y. Parametric investigation on the essential flow factors commanding steady operations of the second throat exhaust diffuser. In 44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit. 2008. (44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit).