0
Research Papers

# Experimental and Numerical Analysis of High Heat Transfer Phenomenon in Minichannel Gaseous Cooling

[+] Author and Article Information
Kazuo Hara, Masato Furukawa

Fluid Science Laboratory, Division of Mechanical Science, Kyushu University, Fukuoka, Japan

Naoki Akihiro

Riso Kagaku Corporation, Ibaraki, Japan

J. Turbomach 130(2), 021017 (Mar 24, 2008) (8 pages) doi:10.1115/1.2751146 History: Received August 23, 2006; Revised October 10, 2006; Published March 24, 2008

## Abstract

The authors have reported that a minichannel flow system had a high heat transfer coefficient. We investigated the heat transfer and flow structure of single and array minichannels combined with an impingement flow system experimentally and numerically. The diameter $D$ of the channel was $1.27mm$, and length to diameter ratio $L∕D$ was 5. The minichannel array was so-called shower head, which was constructed by 19 minichannels located at the apex of equilateral triangle, the side length $S$ of which was $4mm$ a single stage block was used to investigate the heat transfer without impinging flow system. Two stage blocks were combined in series to compose an impingement heat transfer system with an impingement distance of $H$. $H∕D$ ranged from 1.97 to 7.87. The dimensionless temperature increased as the impingement distance became short. A comparison of heat transfer performance was made between minichannel flow and impingement jet by comparing the single- and two-stage heat transfer experiments. It was found that dimensionless temperature of the minichannel exceeded that of the impingement jet. The mechanism of high heat transfer was studied numerically by the Reynolds-averaged Navier-Stokes equation and $k-ω$ turbulence model. The limiting streamline pattern was correlated well to the surface heat flux distribution. The high heat transfer was achieved by suppressing the development of boundary layer under strong pressure gradient near the channel inlet. This heat transfer mechanisms became dominant when the channel size fell into the region of the minichannel.

<>

## Figures

Figure 1

Experimental setup for experiment 1, two stage, for the cases A to L in Table 1. The figure shows for H=5mm and 19 minichannels.

Figure 2

Plane view of minichannel for staggered configuration. The channels of block 1 and block 2 are shown together: (a) single channel and (b) 19 channels.

Figure 3

Detail of the impingement chamber for H=2.5mm and the definition of the name of the heat transfer surface

Figure 4

Experimental setup for experiments 2 and 3: (a) experimental setup for experiment 2, using block 1 with the back pressure valve control for cases M and O in Table 1, and (b) experimental setup for experiment 3 using block 2 without the back pressure valve for the cases N and P in Table 1

Figure 5

Correlation of dimensionless temperature and pressure ratio

Figure 6

Correlation of dimensionless temperature and pressure ratio

Figure 7

Correlation of dimensionless temperature and pressure ratio

Figure 8

Correlation of dimensionless temperature and pressure ratio

Figure 9

Comparison of experiment and CFD result for 19 channel and two stage

Figure 10

Stanton number distribution and pseudo-limitting streamline for single channel and single stage, case N: (a) heat flux on wall 1 and (b) heat flux on wall 2

Figure 11

Correlation of surface heat flux, pressure gradient and static pressure near the channel inlet surface for case N

Figure 12

Stanton number and velocity vector for case C, H=10mm, Stagger arrangement (color scale given in Fig. 1)

Figure 13

Stanton number and velocity vector for case I, H=10mm, stagger arrangement

Figure 14

Stanton number distribution and psuedo-limitting streamline case G, H=2.5 stagger arrangement, N=19: (a) wall 1, (b) wall 2, (c) wall 3, and (d) wall 4

## Errata

Some tools below are only available to our subscribers or users with an online account.

### Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related Proceedings Articles
Related eBook Content
Topic Collections