Future rocket-nozzle extensions have to be thermally protected by a film of cooling gas. The hot supersonic boundary-layer flow may be fully turbulent despite a strong favorable pressure gradient and strongly cooled walls. In contrast to previous investigations, where a laminar boundary-layer state was considered, the present work deals with the effects of a turbulent flow. The cooling film is ...

Numerical simulation is performed in this study to explore filmcooling enhancement by injecting mist into the cooling air with a focus on investigating the effect of various modeling schemes on the simulation results. The effect of turbulence models, dispersed-phase modeling, inclusion of different forces (Saffman, thermophoresis, and Brownian), trajectory tracking, and mist injection scheme is...

The effect of film cooling slot exit area and shape is studied. Detailed heat transfer coefficient and film effectiveness measurements are obtained simultaneously using a single transient IR thermography technique. Two designs with a crescent shaped exit and a slot exit are considered. The results show that the crescent shaped exit provides significantly higher film cooling effectiveness than t...

References 1Al Taweel, A. M., and Landau, J., “Turbulence Modulation in TwoPhase Jets,” International Journal of Multiphase Flow, Vol. 3, No. 2, 1977, pp. 341–351. 2Gore, R. A., and Crowe, C. T., “Effects of Particle Size on Modulating Turbulent Intensity,” International Journal of Multiphase Flow, Vol. 15, No. 2, 1989, pp. 279–285. 3Schreck, S., andKleis, S. J., “ModiŽ cationofGrid-GeneratedTu...

ii response of the wall. For this purpose, the same PSP-sensor is employed for thermography measurements by taking advantage of the inherent temperature sensitivity of this technology. An engine-realistic test case illustrates the capability of the technique under complex flow conditions. It allows to demonstrate that measurements with high spatial resolution can be obtained over large portions...

The knowledge of the thermodynamic process during the cooling of reproductive biological systems is important to assess and optimize the cryopreservation procedures. The time-temperature curve of a sample immersed in liquid nitrogen enables the calculation of cooling rates and helps to determine whether it is vitrified or undergoes phase change transition. When dealing with cryogenic liquids, t...

In this paper, we describe an experimental study of the phenomenon of spray cooling in the case of liquid helium, either normal or superfluid, and its relationship to the heat transfer between an atomized diphasic flow contained in a long pipe, and the pipe walls. This situation is discussed in the context of the cooling of the superconducting magnets of the Large Hadron Collider (LHC). Experim...

Quenching cooling rate of rotary hollow cylinder by one row of water impinging jets has been experimentally studied. Water jets (d = 8 mm) with sub-cooling 55 to 85 ◦C and Reynolds number 8,006 to 36,738 impinged over rotary hot hollow cylinder (rotation speed 10 to 70 rpm) with initial temperature 250 to 600 ◦C. Impingement impact angle of row of jets varied between 0 to 135 ◦ and jet-to-jet s...