Terrence W. Simon

Bio: Terrence W. Simon is an academic researcher from University of Minnesota. The author has contributed to research in topics: Heat transfer & Turbulence. The author has an hindex of 37, co-authored 305 publications receiving 5025 citations. Previous affiliations of Terrence W. Simon include Motorola & DuPont.

Effectiveness of the Gas Turbine Endwall Fences in Secondary Flow Control at Elevated Freestream Turbulence Levels

Abstract: A secondary flow management technique which employs a boundary layer fence on the endwall of a gas turbine passage is evaluated under freestream turbulence conditions that are representative of turbine conditions. A turbulence generator, which was able to reproduce the characteristics of the combustor exit flow, was used. The horseshoe and passage vortices observed in previous tests with low turbulence level remain coherent and strong within the cascade passage when the intensity is elevated to 10 percent. A boundary layer fence on the endwall remains effective in changing the path of the horseshoe vortex and reducing the influence of the vortex on the flow near the suction wall at the high freestream turbulence level. The fence is more effective in reducing the secondary flow for the high turbulence case than for a low 11 case, probably because the vortex which has been deflected into the core flow diffuses and dissipates faster in the more turbulent flow. The fence decreases aerodynamic losses for streamlines within the core of the channel flow. NOMENCLATURE chord� (mm) specific heat of the air (kJ/kgK) total pressure coefficient. (Pt-Ptr)/(0.5pU.2) secondary kinetic energy coefficient, (v2+w2)/UO2 height of the fence� (mm) pressure side leg of horseshoe vortex suction side leg of horseshoe vortex heat transfer coefficient (W/m2K) power spectral density (e.g. u'2(f, df)/di), � (m2/s2) total pressure total pressure in freestream upstream of the cascade Reynolds number Reynolds number based on the chord length curvilinear distance from stagnation line along suction wall (mm)

The Influence of Coolant Supply Geometry on Film Coolant Exit Flow and Surface Adiabatic Effectiveness

Abstract: Experimental hot-wire anemometry and thermocouple measurements are taken to document the sensitivity which film cooling performance has to the hole length and the geometry of the plenum which supplies cooling flow to the holes. This sensitivity is described in terms of the effects these geometric features have on hole-exit velocity and turbulence intensity distributions and on adiabatic effectiveness values on the surface downstream. These measurements were taken under high freestream turbulence intensity (12%) conditions, representative of operating gas turbine engines. Coolant is supplied to the film cooling holes by means of (1) an unrestricted plenum, (2) a plenum which restricts the flow approaching the holes, forcing it to flow co-current with the freestream, and (3) a plenum which forces the flow to approach the holes counter-current with the freestream. Short-hole (L/D = 2.3) and long-hole (L/D = 7.0) comparisons are made. The geometry has a single row of film cooling holes with 35°-inclined streamwise injection. The film cooling flow is supplied at the same temperature as that of the freestream for hole-exit measurements and 10°C above the freestream temperature for adiabatic effectiveness measurements, yielding density ratios in the range 0.96–1.0. Two coolant-to-freestream velocity ratios, 0.5 and 1.0, are investigated. The results document the effects of (1) supply plenum geometry, (2) velocity ratio, and (3) hole L/D.Copyright © 1997 by ASME

Heat Transfer Measurements in a First-Stage Nozzle Cascade Having Endwall Contouring: Misalignment and Leakage Studies

Abstract: This work supports new gas turbine designs for improved performance by evaluating endwall heat transfer rates in a cascade that is representative of a first stage stator passage and incorporates endwall assembly features and leakage. Assembly features, such as gaps in the endwall and misalignment of those gaps, disrupt the endwall boundary layer, typically leading to enhanced heat transfer rates. Leakage flows through such gaps within the passage can also affect endwall boundary layers and may induce additional secondary flows and vortex structures in the passage near the endwall. The present paper documents leakage flow and misalignment effects on the endwall heat transfer coefficients within a passage which has one axially-contoured and one straight endwall. In particular, features associated with the combustor-to-turbine transition piece and the assembly joint on the vane platform are addressed.Copyright © 2006 by ASME

Boiling incipience and nucleate boiling heat transfer of highly-wetting dielectric fluids from electronic materials

Abstract: An experimental study of pool boiling was conducted using cylindrical heater surfaces of platinum, silicon, silicon dioxide, and aluminum oxide. They were immersed in FC-72 and R-113, saturated at 1-a.t.m. pressure. The effects of fluid and surface material on boiling incipience and on the nucleate boiling curve was investigated. A probabilistic representation was used to present the incipience wall superheat values, which scattered widely for ostensibly identical runs. The difference in incipience wall superheat values between those with FC-72 and R-113 was significant, but the surface material effect on boiling incipience was small. The surface material effect was more pronounced in the nucleate boiling regime than on the incipience process. >

Boundary Layer Theory

Abstract: The boundary layer equations for plane, incompressible, and steady flow are $$\matrix{ {u{{\partial u} \over {\partial x}} + v{{\partial u} \over {\partial y}} = - {1 \over \varrho }{{\partial p} \over {\partial x}} + v{{{\partial ^2}u} \over {\partial {y^2}}},} \cr {0 = {{\partial p} \over {\partial y}},} \cr {{{\partial u} \over {\partial x}} + {{\partial v} \over {\partial y}} = 0.} \cr }$$

Numerical Heat Transfer And Fluid Flow

Abstract: Thank you for reading numerical heat transfer and fluid flow. Maybe you have knowledge that, people have search numerous times for their favorite books like this numerical heat transfer and fluid flow, but end up in infectious downloads. Rather than reading a good book with a cup of coffee in the afternoon, instead they cope with some malicious virus inside their computer. numerical heat transfer and fluid flow is available in our digital library an online access to it is set as public so you can get it instantly. Our books collection spans in multiple countries, allowing you to get the most less latency time to download any of our books like this one. Merely said, the numerical heat transfer and fluid flow is universally compatible with any devices to read.

Assessment of high-heat-flux thermal management schemes

Abstract: This paper explores the recent research developments in high-heat-flux thermal management. Cooling schemes such as pool boiling, detachable heat sinks, channel flow boiling, microchannel and mini-channel heat sinks, jet-impingement, and sprays, are discussed and compared relative to heat dissipation potential, reliability, and packaging concerns. It is demonstrated that, while different cooling options can be tailored to the specific needs of individual applications, system considerations always play a paramount role in determining the most suitable cooling scheme. It is also shown that extensive fundamental electronic cooling knowledge has been amassed over the past two decades. Yet there is now a growing need for hardware innovations rather than perturbations to those fundamental studies. An example of these innovations is the cooling of military avionics, where research findings from the electronic cooling literature have made possible the development of a new generation of cooling hardware which promise order of magnitude increases in heat dissipation compared to today's cutting edge avionics cooling schemes.