Thin film coolers can provide large cooling power densities compared to bulk thermoelectrics due to the close spacing of hot and cold junctions. Important parameters in the design of such coolers are investigated theoretically and experimentally. A three-dimensional ~3D! finite element simulator ~ANSYS! is used to model self-consistently thermal and electrical properties of a complete device st...

A Phase Doppler Particle Analyzer (PDPA) system is employed to measure the two-phase mist flow behavior including flow velocity field, droplet size distribution, droplet dynamics, and turbulence characteristics. Based on the droplet measurements made through PDPA, a projected profile describing how the air-mist coolant jet flow spreads and eventually blends into the hot main flow is proposed. T...

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 ...

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...

A wireless and passive temperature sensor operating up to 800 °C is proposed. The sensor is based on microwave backscatter RFID (radio frequency identification) technology. A thin-film planar structure and simple working principle make the sensor easy to operate under high temperature. In this paper, the proposed high temperature sensor was designed, fabricated, and characterized. Here the 99% ...