Computations of Low Pressure Fluid Flow and Heat Transfer in Ducts Using the Direct Simulation Monte Carlo Method

2002 ◽  
Vol 124 (4) ◽  
pp. 609-616 ◽  
Author(s):  
Fang Yan ◽  
Bakhtier Farouk
Keyword(s):  
Heat Transfer ◽  
Monte Carlo ◽  
Noble Gas ◽  
Direct Simulation Monte Carlo ◽  
Low Pressure ◽  
Gas Flows ◽  
Direct Simulation ◽  
Flow And Heat Transfer ◽  
Pressure Profiles ◽  
Simulation Monte Carlo

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.

Computations of Low Pressure Fluid Flow and Heat Transfer in Ducts Using Direct Simulation Monte Carlo Method

1999 ◽  
Author(s):  
Fang Yan ◽  
Bakhtier Farouk
Keyword(s):  
Heat Transfer ◽  
Monte Carlo ◽  
Noble Gas ◽  
Direct Simulation Monte Carlo ◽  
Low Pressure ◽  
Direct Simulation ◽  
Flow And Heat Transfer ◽  
Gas Transport Properties ◽  
Pressure Profiles ◽  
Simulation Monte Carlo

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.

Gas Properties Effects in Microchannel Studies Using Direct Simulation Monte Carlo

2010 ◽  
Author(s):  
Masoud Darbandi ◽  
Abolfazl Karchani ◽  
Hassan Akhlaghi ◽  
Gerry Schneider
Keyword(s):  
Heat Transfer ◽  
Monte Carlo ◽  
Slip Flow ◽  
Direct Simulation Monte Carlo ◽  
Direct Simulation ◽  
Polyatomic Gases ◽  
Flow And Heat Transfer ◽  
Flow Through ◽  
Simulation Monte Carlo ◽  
Gas Properties

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.

Two-Dimensional Unstructured Direct Simulation Monte Carlo Method for Micro/Nanochannel Gas Flows

2009 ◽  
Author(s):  
Mehrdad Raisee ◽  
Mahmood Mohammadi Shad ◽  
Seyyed Mostafa Hosseinalipoor ◽  
Samaneh Farokhirad
Keyword(s):  
Monte Carlo ◽  
Gas Dynamics ◽  
Direct Simulation Monte Carlo ◽  
Molecular Gas ◽  
Gas Flows ◽  
Two Dimensional ◽  
Direct Simulation ◽  
Heat Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Simulation Monte Carlo

In this paper, the fluid flow and heat transfer characteristics of two-dimensional micro/nanochannel flows are examined. The Direct Simulation Monte Carlo (DSMC) method for molecular gas dynamics is utilized to simulate the gas flows through two-dimensional micro/nanochannel. The collision process has been treated in a statistical way using the no-time-counter (NTC) scheme and the variable hard sphere (VHS) model has been employed to simulate the collision from the kinetic viewpoint. Results revealed that the temperature and velocity distributions have an unequalled behavior and may have a significant effect on the advancement and the design of MEMS and NEMS.

Study on the Deposition Profile Characteristics in the Micron-Scale Trench Using Direct Simulation Monte Carlo Method

1998 ◽  
Vol 120 (2) ◽  
pp. 296-302 ◽  
Author(s):  
Masato Ikegawa ◽  
Jun’ichi Kobayashi ◽  
Morihisa Maruko
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Boundary Conditions ◽  
Gas Flow ◽  
Direct Simulation Monte Carlo ◽  
Low Pressure ◽  
Sputter Deposition ◽  
Direct Simulation ◽  
Simulation Monte Carlo ◽  
Profile Characteristics

As integrated circuits are advancing toward smaller device features, step-coverage in submicron trenches and holes in thin film deposition are becoming of concern. Deposition consists of gas flow in the vapor phase and film growth in the solid phase. A deposition profile simulator using the direct simulation Monte Carlo method has been developed to investigate deposition profile characteristics on small trenches which have nearly the same dimension as the mean free path of molecules. This simulator can be applied to several deposition processes such as sputter deposition, and atmospheric- or low-pressure chemical vapor deposition. In the case of low-pressure processes such as sputter deposition, upstream boundary conditions of the trenches can be calculated by means of rarefied gas flow analysis in the reactor. The effects of upstream boundary conditions, molecular collisions, sticking coefficients, and surface migration on deposition profiles in the trenches were clarified.

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