Free convection of gas mixture above a flat horizontal plate in constant-velocity flow

1976 ◽  
Vol 31 (3) ◽  
pp. 1095-1100 ◽  
Author(s):  
A. A. Pirozhenko
Keyword(s):  
Free Convection ◽  
Constant Velocity ◽  
Gas Mixture ◽  
Horizontal Plate ◽  
Velocity Flow

Numerical and experimental study of free convection above a sinusoidal horizontal plate

2003 ◽  
Vol 39 (3) ◽  
pp. 183-194 ◽  
Author(s):  
S. Pretot ◽  
B. Zeghmati ◽  
J. Bresson
Keyword(s):  
Experimental Study ◽  
Free Convection ◽  
Horizontal Plate

Even-echo rephasing and constant velocity flow

1987 ◽  
Vol 4 (5) ◽  
pp. 422-430 ◽  
Author(s):  
J. Katz ◽  
R. M. Peshock ◽  
C. R. Malloy ◽  
S. Schaefer ◽  
R. W. Parkey
Keyword(s):  
Constant Velocity ◽  
Velocity Flow

Free Convection on a Horizontal Plate With Blowing and Suction

1988 ◽  
Vol 110 (3) ◽  
pp. 793-796 ◽  
Author(s):  
Hsiao-Tsung Lin ◽  
Wen-Shing Yu
Keyword(s):  
Free Convection ◽  
Horizontal Plate

Droplet Burning and Evaporation Times for Distillate and Residual Fuel Oils

1980 ◽  
Author(s):  
P. C. T. de Boer
Keyword(s):  
Gas Turbine ◽  
Constant Velocity ◽  
Droplet Diameter ◽  
Diffusion Constant ◽  
Gas Mixture ◽  
Residual Oil ◽  
Gas Turbine Combustor ◽  
Initial Droplet ◽  
Fuel Oils ◽  
Industrial Gas Turbine

Estimates are given of the burning and evaporation times of No. 2 distillate and No. 6 residual oil droplets, under conditions typical of industrial gas turbine combustors. Account is taken of the temperature dependence of the specific heat, the diffusion constant, and the thermal conductivity of the gas mixture surrounding the droplet. Detailed calculations are presented of the factor by which the droplet lifetime is reduced as a result of convection, for the case that the droplet is released in a gas moving at constant velocity. This factor is on the order of four for the conditions of interest. Using estimates of initial droplet diameter based on data reported by Jasuja, it is found that the ratio of characteristic droplet burning time to characteristic droplet residence time in a typical industrial gas turbine combustor is much smaller than 1 for distillate oil, but may be on the order of 1 for residual oil.

On the Heat Transfer Enhancement of Turbulent Gas Floes in Short Round Tubes Engaging a Light Gas Mixed With Selected Heavier Gases

2011 ◽  
Author(s):  
Neda Mobinipouya ◽  
Omid Mobinipouya
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Free Convection ◽  
Constant Pressure ◽  
Gas Mixtures ◽  
Global Maximum ◽  
Gas Mixture ◽  
Kinetic Theory Of Gases ◽  
Gas Composition ◽  
Convection Coefficient

A unique way for maximizing turbulent free convection from heated vertical plates to cold gases is studied in this paper. The central idea is to examine the attributes that binary gas mixtures having helium as the principal gas and xenon, nitrogen, oxygen, carbon dioxide, methane, tetrafluoromethane and sulfur hexafluoride as secondary gases may bring forward. From fluid physics, it is known that the thermo-physical properties affecting free convection with binary gas mixtures are viscosity ηmix, thermal conductivity λmix, density ρmix, and heat capacity at constant pressure. The quartet ηmix, λmix, ρmix, and Cp,mix is represented by triple-valued functions of the film temperature the pressure P, and the molar gas composition w. The viscosity is obtained from the Kinetic Theory of Gases conjoined with the Chapman-Enskog solution of the Boltzmann Transport Equation. The thermal conductivity is computed from the Kinetic Theory of Gases. The density is determined with a truncated virial equation of state. The heat capacity at constant pressure is calculated from Statistical Thermodynamics merged with the standard mixing rule. Using the similarity variable method, the descriptive Navier-Stokes and energy equations for turbulent Grashof numbers Grx > 109 are transformed into a system of two nonlinear ordinary differential equations, which is solved by the shooting method and the efficient fourth-order Runge-Kutta-Fehlberg algorithm. The numerical temperature fields T(x, y) for the five binary gas mixtures He-Xe, He-N2, He-O2, He-CO2, He-CH4, He-CF4 and He-SF6 are channeled through the allied mean convection coefficient hmix/B varying with the molar gas composition w in proper w-domain [0, 1]. For the seven binary gas mixtures utilized, the allied mean convection coefficient hmix/B versus the molar gas composition w is graphed in congruous diagrams. At a low film temperature Tf = 300 K, the global maximum allied mean convection coefficient hmix,max/B = 85 is furnished by the He-SF6 gas mixture at an optimal molar gas composition wopt = 0.93. The global maximum allied mean convection coefficient hmix,max/B = 57 is supplied by pure methane gas SF6 (w = 1) at a high film temperature Tf = 1000 K instead of the He-SF6 gas mixture.

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