Turbine Blade Heat Transfer Prediction Using Coupled Turbulent Prandtl Number and Transition Models

1991 ◽  
Author(s):  
Kevin W. Whitaker
Keyword(s):  
Heat Transfer ◽  
Prandtl Number ◽  
Turbine Blade ◽  
Turbulent Prandtl Number ◽  
Transition Models

Numerical Investigation of Gas Turbine Combustor Liner Film Cooling Slots

2018 ◽  
Author(s):  
Firat Kiyici ◽  
Ahmet Topal ◽  
Ender Hepkaya ◽  
Sinan Inanli
Keyword(s):  
Heat Transfer ◽  
Prandtl Number ◽  
Surface Temperature ◽  
Gas Turbine ◽  
Film Cooling ◽  
Turbulent Prandtl Number ◽  
Surface Cooling ◽  
Gas Turbine Combustor ◽  
Cooling Effectiveness ◽  
Combustor Liner

A numerical study, based on experimental work of Inanli et al. [1] is conducted to understand the heat transfer characteristics of film cooled test plates that represent the gas turbine combustor liner cooling system. Film cooling tests are conducted by six different slot geometries and they are scaled-up model of real combustor liner. Three different blowing ratios are applied to six different geometries and surface cooling effectiveness is determined for each test condition by measuring the surface temperature distribution. Effects of geometrical and flow parameters on cooling effectiveness are investigated. In this study, Conjugate Heat Transfer (CHT) simulations are performed with different turbulence models. Effect of the turbulent Prandtl Number is also investigated in terms of heat transfer distribution along the measurement surface. For this purpose, turbulent Prandtl number is calculated with a correlation as a function of local surface temperature gradient and its effect also compared with the constant turbulent Prandtl numbers. Good agreement is obtained with two-layered k–ϵ with modified Turbulent Prandtl number.

Heat transfer in a turbulent channel flow with square bars or circular rods on one wall

2015 ◽  
Vol 776 ◽  
pp. 512-530 ◽  
Author(s):  
S. Leonardi ◽  
P. Orlandi ◽  
L. Djenidi ◽  
R. A. Antonia
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Prandtl Number ◽  
Channel Flow ◽  
Turbulent Channel Flow ◽  
Turbulent Heat ◽  
Turbulent Prandtl Number ◽  
Smooth Wall ◽  
Roughness Elements ◽  
Smooth Channel

Direct numerical simulations (DNS) are carried out to study the passive heat transport in a turbulent channel flow with either square bars or circular rods on one wall. Several values of the pitch (${\it\lambda}$) to height ($k$) ratio and two Reynolds numbers are considered. The roughness increases the heat transfer by inducing ejections at the leading edge of the roughness elements. The amounts of heat transfer and mixing depend on the separation between the roughness elements, an increase in heat transfer accompanying an increase in drag. The ratio of non-dimensional heat flux to the non-dimensional wall shear stress is higher for circular rods than square bars irrespectively of the pitch to height ratio. The turbulent heat flux varies within the cavities and is larger near the roughness elements. Both momentum and thermal eddy diffusivities increase relative to the smooth wall. For square cavities (${\it\lambda}/k=2$) the turbulent Prandtl number is smaller than for a smooth channel near the wall. As ${\it\lambda}/k$ increases, the turbulent Prandtl number increases up to a maximum of 2.5 at the crests plane of the square bars (${\it\lambda}/k=7.5$). With increasing distance from the wall, the differences with respect to the smooth wall vanish and at three roughness heights above the crests plane, the turbulent Prandtl number is essentially the same for smooth and rough walls.

Numerical Investigation on Heat Transfer of Supercritical Water With a Variable Turbulent Prandtl Number Model

2020 ◽  
Vol 6 (3) ◽  
Author(s):  
Xiangfei Kong ◽  
Dongfeng Sun ◽  
Lingtong Gou ◽  
Siqi Wang ◽  
Nan Yang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Prandtl Number ◽  
Supercritical Fluids ◽  
Supercritical Water ◽  
Viscosity Ratio ◽  
Turbulent Viscosity ◽  
Turbulence Models ◽  
Turbulent Prandtl Number ◽  
Vertical Tubes

Abstract Turbulent Prandtl number (Prt) has a great impact on the performance of turbulence models in predicting heat transfer of supercritical fluids. Unrealistic treatment of Prt may lead to large deviations of the prediction results from experimental data under supercritical conditions. In this study, the effect of Prt on heat transfer of supercritical water was extensively studied by using shear stress transport (SST) k–ω turbulence model, and the results suggested that using the existing Prt models would lead to failures in predicting the heat transfer characteristics of supercritical water under deteriorated heat transfer (dht) conditions. A new variable Prt model was proposed with the Prt varied with pressure, turbulent viscosity ratio, and molecular Prandtl number. The new model was validated by comparing the numerical results with the corresponding experimental data, and it was found that the new variable Prt model exhibited better performance on reproducing the dht of supercritical water in vertical tubes than those of the existing Prt models.

A Model for Eddy Conductivity and Turbulent Prandtl Number

1973 ◽  
Vol 95 (2) ◽  
pp. 227-234 ◽  
Author(s):  
T. Cebeci
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Prandtl Number ◽  
Turbulent Flows ◽  
Pressure Gradients ◽  
Turbulent Prandtl Number ◽  
Temperature Distributions ◽  
Type Flow ◽  
Prandtl Numbers ◽  
Experimental Findings

This paper presents a model for eddy conductivity and turbulent Prandtl number based on the considerations of a Stokes-type flow. The expressions obtained by the model provide continuous velocity and temperature distributions for turbulent flows and are applicable to flows with pressure gradients, mass transfer, and heat transfer. Close to the wall the turbulent Prandtl number appears to be strongly affected by the molecular Prandtl number; away from the wall it is constant, that is, it is independent of the molecular Prandtl number. Calculated results agree well with experiments, including those with fluids having both low and high Prandtl numbers. In addition the results confirm recent experimental findings, in that the mass transfer has no effect on turbulent Prandtl number.

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