### Abstract

Flows in uniform, parallel, and series microchannels have been investigated using the direct simulation Monte Carlo (DSMC) method. For the uniform microchannel cases, at higher pressure ratio, mixed Kn-regime flows were observed, where the Knudsen number (Kn) varies from below 0.1 to above 0.1. Also, the higher pressure ratio makes the flow accelerate more as the flow develops through the uniform microchannel In order to examine the heat transfer characteristics between the wall and the bulk flow, a linear temperature distribution was imposed on the wall. Most of the wall heat flux occurs within the channel entrance region while it remains a constant with a slight magnitude along the rest of the channel wall. For the series microchannel cases, the computational domain was established by adding three surfaces and excluding one region from the rectangular domain. Diffuse effects were observed near the interface of the two segments, where the flow upstream the interface can be either heated or cooled by the flow down-stream depending on their temperature difference. In addition, the effect of the gas species was investigated by conducting the simulation using helium and argon respectively. It can be found that the speed of the gas with lighter molecular mass is much higher than that of the heavier gas. The computational domain of the parallel microchannel was established similarly to that of the series microchannel. Under a certain pressure ratio, more pressure drop occurs in the parallel parts as the gap height increases. The recirculation phenomenon was observed after the gap wall between the two parallel parts and was evaluated quantitatively in the present study by defining a parameter called the developing coefficient. The gap height between the two parallel parts has only slight effect of the flow development.

Original language | English |
---|---|

Pages (from-to) | 1153-1163 |

Number of pages | 11 |

Journal | Journal of Fluids Engineering, Transactions of the ASME |

Volume | 128 |

Issue number | 6 |

DOIs | |

Publication status | Published - Nov 2006 |

Externally published | Yes |

### Fingerprint

### Keywords

- DSMC
- Microchannel heat transfer
- Parallel and series microchannels

### ASJC Scopus subject areas

- Mechanical Engineering
- Fluid Flow and Transfer Processes

### Cite this

*Journal of Fluids Engineering, Transactions of the ASME*,

*128*(6), 1153-1163. https://doi.org/10.1115/1.2354525

**DSMC simulation of subsonic flows in parallel and series microchannel.** / Le, M.; Hassan, Ibrahim; Esmail, N.

Research output: Contribution to journal › Article

*Journal of Fluids Engineering, Transactions of the ASME*, vol. 128, no. 6, pp. 1153-1163. https://doi.org/10.1115/1.2354525

}

TY - JOUR

T1 - DSMC simulation of subsonic flows in parallel and series microchannel

AU - Le, M.

AU - Hassan, Ibrahim

AU - Esmail, N.

PY - 2006/11

Y1 - 2006/11

N2 - Flows in uniform, parallel, and series microchannels have been investigated using the direct simulation Monte Carlo (DSMC) method. For the uniform microchannel cases, at higher pressure ratio, mixed Kn-regime flows were observed, where the Knudsen number (Kn) varies from below 0.1 to above 0.1. Also, the higher pressure ratio makes the flow accelerate more as the flow develops through the uniform microchannel In order to examine the heat transfer characteristics between the wall and the bulk flow, a linear temperature distribution was imposed on the wall. Most of the wall heat flux occurs within the channel entrance region while it remains a constant with a slight magnitude along the rest of the channel wall. For the series microchannel cases, the computational domain was established by adding three surfaces and excluding one region from the rectangular domain. Diffuse effects were observed near the interface of the two segments, where the flow upstream the interface can be either heated or cooled by the flow down-stream depending on their temperature difference. In addition, the effect of the gas species was investigated by conducting the simulation using helium and argon respectively. It can be found that the speed of the gas with lighter molecular mass is much higher than that of the heavier gas. The computational domain of the parallel microchannel was established similarly to that of the series microchannel. Under a certain pressure ratio, more pressure drop occurs in the parallel parts as the gap height increases. The recirculation phenomenon was observed after the gap wall between the two parallel parts and was evaluated quantitatively in the present study by defining a parameter called the developing coefficient. The gap height between the two parallel parts has only slight effect of the flow development.

AB - Flows in uniform, parallel, and series microchannels have been investigated using the direct simulation Monte Carlo (DSMC) method. For the uniform microchannel cases, at higher pressure ratio, mixed Kn-regime flows were observed, where the Knudsen number (Kn) varies from below 0.1 to above 0.1. Also, the higher pressure ratio makes the flow accelerate more as the flow develops through the uniform microchannel In order to examine the heat transfer characteristics between the wall and the bulk flow, a linear temperature distribution was imposed on the wall. Most of the wall heat flux occurs within the channel entrance region while it remains a constant with a slight magnitude along the rest of the channel wall. For the series microchannel cases, the computational domain was established by adding three surfaces and excluding one region from the rectangular domain. Diffuse effects were observed near the interface of the two segments, where the flow upstream the interface can be either heated or cooled by the flow down-stream depending on their temperature difference. In addition, the effect of the gas species was investigated by conducting the simulation using helium and argon respectively. It can be found that the speed of the gas with lighter molecular mass is much higher than that of the heavier gas. The computational domain of the parallel microchannel was established similarly to that of the series microchannel. Under a certain pressure ratio, more pressure drop occurs in the parallel parts as the gap height increases. The recirculation phenomenon was observed after the gap wall between the two parallel parts and was evaluated quantitatively in the present study by defining a parameter called the developing coefficient. The gap height between the two parallel parts has only slight effect of the flow development.

KW - DSMC

KW - Microchannel heat transfer

KW - Parallel and series microchannels

UR - http://www.scopus.com/inward/record.url?scp=33751440656&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33751440656&partnerID=8YFLogxK

U2 - 10.1115/1.2354525

DO - 10.1115/1.2354525

M3 - Article

VL - 128

SP - 1153

EP - 1163

JO - Journal of Fluids Engineering, Transactions of the ASME

JF - Journal of Fluids Engineering, Transactions of the ASME

SN - 0098-2202

IS - 6

ER -