Occurrence of Hysteresis like behavior of resistance of Sb 2 Te 3 film in heating-cooling cycle. Abstract Experimental observations of a peculiar behavior observed on heating and cooling Sb 2 Te 3 films at different heating and cooling rate are detailed. The film regained its original resistance, forming a closed loop, on the completion of the heating-cooling cycle which was reproducible for id...

An experimental investigation of the local film cooling effectiveness and heat transfer coefficient downstream of a row of elongated holes in a simulated axial turbine blade tip is presented. Film cooling is needed to protect the turbine blade tip region from high heat transfer rates, especially when cooling by convection is insufficient to keep the temperature distribution of the blade within ...

Abstract—There is a gap at combustor-turbine interface where leakage flow comes out to prevent hot gas ingestion into the gas turbine nozzle platform. The leakage flow protects the nozzle endwall surface from the hot gas coming from combustor exit. For controlling flow’s stream, the gap’s geometry is transformed by changing fillet radius size. During the operation, step configuration is occurre...

Modeling and optimization of bulk SiGe thin-film coolers are described. Thin-film coolers can provide large cooling power densities compared to commercial thermoelectrics. Thin-film SiGe coolers have been demonstrated with maximum cooling of 4◦C at room temperature and with cooling power density exceeding 500 W/cm2. Important parameters in the design of such coolers are investigated theoretical...

To achieve high thermal efficiency in modern gas turbines, the turbine-inlet temperature has to be increased. In response to such requisites and to prevent thermal failure of the components exposed to hot gas streams, the use of different cooling techniques, including film cooling, is essential. Finding an optimum film cooling design has become a challenge as it is influenced by a large number ...

the present article focuses on the evaluation of a first-moment closure model applicable to film cooling flow and heat transfer computations. the present first-moment closure model consists of a higher level of turbulent heat flux modeling in which two additional transport equations for temperature variance kθ and its dissipation rate εθ are considered. it not only employs a time scale that is ...

An experimental study was performed to examine effects of compressibility on film cooling effectiveness for coolant flowing from cylindrical holes in a flat plate. The incoming flow Mach number was set at 0.07, 0.30, 0.50 and 0.70. The Pressure Sensitive Paint (PSP) technique, which is based on a mass transfer analogy, was used to map the adiabatic film cooling effectiveness distribution on the...

To protect turbine endwall from heat damage of hot exhaust gas, film cooling is the most significant method. The complex vortex structures on endwall, such as development horseshoe vortices and transverse flow, affects coverage endwall. In this study, effects gas thermophysical properties full-range a vane are investigated. Three kinds models considered, i.e., constant property model, ideal rea...

We have used variable cooling rate ellipsometric measurements to probe the slow dynamics in thin supported polystyrene films. For the slowest cooling rates (approximately 1 K/min) the measured Tg values are reduced below the bulk value with the measured Tg of 341 K for a 6 nm film. As the cooling rate is increased the Tg reductions become smaller until at cooling rates >90 K/min there is only s...