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공압시험용 플러그 노즐의 핀틀 형상 및 작동압력에 따른 유동 특성 분석
김정진(Jeongjin Kim),오석진(Seokjin Oh),허준영(Junyoung Heo),이도형(Dohyung Lee) 한국추진공학회 2018 한국추진공학회 학술대회논문집 Vol.2018 No.12
공압시험용 플러그 노즐 구동에 따른 추력제어, 핀틀 형상 및 작동압력에 따른 유동특성 분석을 수행하였다. 이를 위해 시험에서의 유동구조와 추력계수를 비교함으로써 수치해석의 타당성을 확인하였다. 이후 각 노즐형상이 설계의도지점에 노즐목이 형성됨과 원뿔형 노즐에 대하여 핀틀 구동만으로 1:8의 추력제어가 가능함을 확인하였다. 마지막으로 고도보정 효과가 뛰어난 에어로 스파이크 노즐일지라도, 너무 높은 NPR에 맞춰 설계된 경우, 과팽창 조건에서 불리할 가능성을 확인하였다. The thrust control calculation according to the operation of plug nozzle for cold air test and the analysis of flow characteristics of pintle shape and operation pressure are performed. For this purpose, the numerical computation was verified in advance by comparing the flow structure and coefficient of thrust with experimental data. Subsequently, it was confirmed that nozzle throat were formed at the design positions on each pintle shape, and 1:8 thrust control was possible only with pintle operation. Finally, although aerospike nozzle has excellent altitude correction, it was found to be unfavourable under overexpansion condition if it designed for too high NPR.
김중근(Joung Keun Kim),이지형(Ji Hyung Lee),장홍빈(Hong Been Chang) 한국추진공학회 2009 한국추진공학회지 Vol.13 No.2
Both the nozzle expansion ratio and the chamber pressure are simultaneously and continuously changed according to pintle movement, resulting in a different internal flow structure and flow separation characteristics. In this paper, the pintle position effect on nozzle flow structure and separation phenomena is analyzed by experimental-aided Computational Fluid Dynamic(CFD). Among the turbulent models for RANS(Reynold Averaged Navier Stokes) in Fluent, Spalart-Allmaras model is better agreement with the nozzle wall pressure distribution attained by cold-flow test than other models. And even if a conical nozzle is used, there is a shock structure similar to cap-shock pattern mainly occurred in contoured or shaped optimized nozzle because of internal shock generated from pintle tip flow separation.
공압시험용 플러그 노즐의 핀틀 형상 및 작동압력에 따른 유동 특성 분석
김정진(Jeongjin Kim),오석진(Seokjin Oh),허준영(Junyoung Heo),이도형(Dohyung Lee) 한국추진공학회 2019 한국추진공학회지 Vol.23 No.3
The thrust control calculation according to the operation of plug nozzle for cold air test and the analysis of the flow characteristics of the pintle shape and operation pressure are performed. The numerical computation was verified by comparing the flow structure and the coefficient of thrust with the experimental data. It was confirmed that the nozzle throat was formed at the design position on each pintle shape, and thrust control up to 1:8 was achieved only by the stroke change. Finally, although the aerospike nozzle is autonomous, it is unfavorable in the under_expansion condition, if it is designed for a very low nozzle pressure ratio.