Heat Transfer in Noble Gases Using Direct Simulation Monte Carlo Technique (DSMC)

2002 ◽  
Vol 2 (12) ◽  
pp. 1050-1056 ◽  
Author(s):  
Mohamed M. Elafify . ◽  
Khalil M. Elawadly . ◽  
Sherif G. Elsharkawy . ◽  
M. Bassiouny .
1999 ◽  
Author(s):  
Fang Yan ◽  
Bakhtier Farouk

Abstract High Knudsen (Kn) number flows are found in vacuum and micro-scale systems. Such flows are characterized by non-continuum behavior. For gases, the flows are usually in the slip or transition regimes. In this paper, the direct simulation Monte Carlo (DSMC) method has been applied to compute low pressure, high Kn flow fields in partially heated channels. Computations were carried out for nitrogen, argon, hydrogen, oxygen and noble gas mixtures. Variation of the Kn is obtained by reducing the pressure while keeping the channel width constant. Nonlinear pressure profiles along the channel centerline are observed. Heat transfer from the channel walls is also calculated and compared with the Graetz solution. The effects of varying pressure, inlet flow and gas transport properties (Kn, Reynolds number, Re and the Prandtl number, Pr respectively) on the wall heat transfer (Nu) were examined. A simplified correlation for predicting Nu¯ as a function of Pe¯ and Kn¯ is presented.


Author(s):  
Masoud Darbandi ◽  
Abolfazl Karchani ◽  
Hassan Akhlaghi ◽  
Gerry Schneider

This paper concern is to study the gas properties effect in flow and heat transfer behaviors through microchannels using the direct simulation Monte Carlo method. The flow is rarefied and supersonic. The channels are investigated at two different inlet boundary conditions. The collision process is modeled using the NTC (no-time-counter) scheme. The VHS model is chosen to simulate collision between particle pairs. The study is provided for many different gases including nitrogen, helium, and oxygen. The Knudsen number is chosen in a manner to provide slip flow through the channel. The results show that the heat transfer from the wall is lower for heavier gases. A comparative study among the monatomic, diatomic, polyatomic gases shows that the heat transfer rate is lower for the polyatomic gases. The result shows that, the heat transfer from the wall is lower for the heavier gases than that for the lighter gas. For a fixed Mach number, the heat transfer from the wall decreases as the molecular diameter increases.


10.2514/3.926 ◽  
1997 ◽  
Vol 11 ◽  
pp. 489-496
Author(s):  
Rong F. Huang ◽  
Han W. Lee ◽  
C. Mavriplis ◽  
J. C. Ahn ◽  
R. Goulard

2018 ◽  
Vol 17 (4-5) ◽  
pp. 425-437 ◽  
Author(s):  
Y Fang ◽  
WW Liou

The direct simulation Monte Carlo method is applied in this paper to simulate the micro Rayleigh-Bénard convection for the Rayleigh number of 10,159 and the Knudsen number of 0.01 in a time-dependent manner. A monatomic gas is enclosed between two infinite, parallel plates with the bottom plate at a higher temperature. Cases of three different computational domain sizes in the horizontal directions are simulated. Evolutions of the convective flow unsteady disturbances patterns and the wall heat transfer are studied in detail. Three stages of distinct flow characteristics can be identified as the flows develop from an initially uniform state. In the first stage, the heat is transferred mainly by conduction. The onset of the vortical flow structures marks the beginning of the second stage. Significant differences in the flow and the heat transfer characteristics are observed in the third stage of the three simulated flows. It is found that the simulated microflows develop vortex rolls that advect along the plates at uniform speeds, which has not been reported previously.


2002 ◽  
Vol 124 (4) ◽  
pp. 609-616 ◽  
Author(s):  
Fang Yan ◽  
Bakhtier Farouk

High Knudsen number (Kn) gas flows are found in vacuum and micro-scale systems. Such flows are usually in the slip or transition regimes. In this paper, the direct simulation Monte Carlo (DSMC) method has been applied to compute low pressure, high Kn flow fields in partially heated channels. Computations were carried out for nitrogen, argon, hydrogen, oxygen and noble gas mixtures. Variation of the Kn is obtained by reducing the pressure while keeping the channel width constant. Nonlinear pressure profiles along the channel centerline are observed. Heat transfer from the channel walls is also calculated and compared with the classical Graetz solution. The effects of varying pressure, inlet flow and gas transport properties (Kn, Reynolds number, Re and the Prandtl number, Pr respectively) on the wall heat transfer (Nusselt number, Nu) were examined. A simplified correlation for predicting Nu¯ as a function of the Peclet number, Pe¯ and Kn¯ is presented.


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