A Balance for Measurement of Yaw , Lift and Drag on a Model in a Hypersonic Shock Tunnel
Lift and Drag on a lifting model with typical control surfaces, in a hypersonic impulse facility. The model used in the present study is a blunt-nosed triangular plate attached with flaps. The experiments were carried out at a freestream Mach number of 8 in a hypersonic shock tunnel, with air as the test gas, where the test time was about 1.2 milliseconds. The experiments were repeated at different angles of incidence of the model and the coefficients of Yawing moment (C Y), Lift (C L) and Drag (C D) were deduced based on the acceleration signals obtained from the balance. Measured values of the moment and force coefficients were compared with the theoretical results predicted using the Newtonian theory.
Measurement of Drag on a Scramjet Engine in a Shock Tunnel
The net drag on a non-fuelled, internal compression, constant-area combustor scramjet engine was measured using a single-component accelerometer balance in a shock tunnel at a freestream Mach number of 8 and a flow total enthalpy of 1.35 MJ/kg. The flow fields of the model were simulated using a commercial CFD code in order to understand the aerodynamics of the engine and compare with the measured net drag co-efficient. Measured and computed values of the net drag co-efficient were found to be in a good agreement.
Effects of reservoir volume on performance of pulse tube cooler.
A pulse tube cooler has the advantages of long-life and low-vibration over conventional cryocoolers such as G-M and Stirling coolers because of the absence of moving parts at low temperature. On the other hand, the combination of a reservoir and orifice is indispensable to optimize the performance of pulse tube coolers. In order to make the pulse tube cooler compact for practical applications, the volume of reservoir should be minimized. This paper analyzes the effects of the reservoir volume on the thermodynamic performance of various components in a simple orifice and a double-inlet pulse tube cooler by combining a linearized model with a thermodynamic analysis. Expressions of entropy production for those components are presented. The results show that the reservoir volume has a significant influence on the entropy production in the various components when the reservoir to pulse tube volume ratio is smaller than about 5. The ratio is important to determine the minimum reservoir volume for a pulse tube cooler. Optimum settings for a double-inlet pulse tube cooler are also discussed.