A numerical optimization of high altitude testing facility for wind tunnel experiments

Abstract

High altitude test facilities are required to test the high area ratio nozzles operating at the upper stages of rocket in the nozzle full flow conditions. It is typically achieved by creating the ambient pressure equal or less than the nozzle exit pressure. On average, air/GN 2 is used as active gas for ejector system that is stored in the high pressure cylinders. The wind tunnel facilities are used for conducting aerodynamic simulation experiments at/under various flow velocities and operating conditions. However, constructing both of these facilities require more laboratory space and expensive instruments. Because of this demerit, a novel scheme is implemented for conducting wind tunnel experiments by using the existing infrastructure available in the high altitude testing (HAT) facility. This article presents the details about the methods implemented for suitably modifying the sub-scale HAT facility to conduct wind tunnel experiments. Hence, the design of nozzle for required area ratio A/A * , realization of test section and the optimized configuration are focused in the present analysis. Specific insights into various rocket models including high thrust cryogenic engines and their holding mechanisms to conduct wind tunnel experiments in the HAT facility are analyzed. A detailed CFD analysis is done to propose this conversion without affecting the existing functional requirements of the HAT facility.

Numerical Analysis of Unsteady Characteristics of the Second Throat of a Transonic Wind Tunnel

“…There is a subsonic speed gap at the choking position, and pressure fluctuations will propagate upstream into the test section through the shock gap [12]. Rose's experiments showed that pressure disturbances downstream of the shock could affect the pressure in the test section through the upstream propagation of the boundary layer [41]. Therefore, the fluctuation in airflow in the test section is inevitable.…”