Equivalent direct connect free-stream shock tunnel conditions for injection locations in an axisymmetric scramjet

Fuel injection optimisation into radical farming scramjets is one of the key technologies being developed at the University of Queensland [18, 6, 13]. To facilitate the experimental testing of some these injection techniques, equivalent tunnel free-stream conditions at the injection locations had to be determined. To compare against previous work [19, 3] and intended flight test data [20] the free-stream conditions were calculated relative to the intended 48 kPa constant dynamic pressure trajectory of the SCRAMSPACE vehicle [4]. Due to the variation of the equivalent standard atmosphere through the test period (33-27 km [20]) and the discreet nature of the nozzles available on the tunnel, the constraining variable used to calculate the conditions was not the flight enthalpy but the ramp injection Mach number; which is the reverse to the standard procedure [10, 15]. By constraining the nozzle exit Mach number, the equivalent flight enthalpy could be determined from the projected flight dynamic pressure and reverse calculating the inviscid conical shocks of the truncated Busemann inlet. Using this equivalent flight enthalpy, a multi-dimensional Kriging based surrogate model was developed to give a surface response to the equivalent tunnel conditions of flows produced in the T4 Hypersonic Shock Tunnel. The final calculated conditions are estimated to be tuned but not necessarily tailored due to the constant compression ratios used in the facility [9]

Process development for high-efficiency silicon solar cells

Fabrication of high-efficiency silicon solar cells in an industrial environment requires a different optimization than in a laboratory environment. Strategies are presented for process development of high-efficiency silicon solar cells, with a goal of simplifying technology transfer into an industrial setting. The strategies emphasize the use of statistical experimental design for process optimization, and the use of baseline processes and cells for process monitoring and quality control. 8 refs

Fluid-solid heat exchange in porous media for transpiration cooling systems

This paper presents a semi-analytical solution of the coupled differential equations for fluid and solid phase in a one-dimensional porous medium in thermal non-equilibrium. The thermal impulse response of the fluid and solid phases is used to determine the pressure loss over the thickness of the material. Experimental data obtained from surface heating of porous ZrB2 samples is compared to the theoretical model. The plenum pressure, surface temperature and backside temperature are measured using pressure sensors, thermographic imaging and thermocouple instrumentation The non-integer system identification (NISI) approach is used to obtain the thermal impulse response which is then compared with the model prediction. Plenum pressure rise and thermal impulse response of the heating experiments are used to assess the volumetric heat transfer coefficient of the sample. Good agreement is found between the simulated and experimental data for the temperature and pressure measurements. The obtained heat transfer coefficients are between 2.1 · 104 and 6.8 · 104 W m−3 K−1 for mass fluxes of 10 to 244 g m−2 s −1

Communication Research

Communication ResearchContains reports on seven research projects