0
Research Papers

Multi-Layer Mini-Channel and Ribbed Mini-Channel Based High Performance Cooling Configurations for Automotive Inverters—Part A: Design and Evaluation

[+] Author and Article Information
Srinath V. Ekkad

e-mail: sekkad@vt.edu
Department of Mechanical Engineering,
Virginia Tech,
Blacksburg, VA 24061

Khai Ngo

Department of Electrical and Computer Engineering,
Virginia Tech,
Blacksburg, VA 24061

1Corresponding author.

Manuscript received June 27, 2012; final manuscript received January 7, 2013; published online June 25, 2013. Assoc. Editor: Bengt Sunden.

J. Thermal Sci. Eng. Appl 5(3), 031010 (Jun 25, 2013) (13 pages) Paper No: TSEA-12-1097; doi: 10.1115/1.4023604 History: Received June 27, 2012; Revised January 07, 2013

Necessitated by the dwindling supply of petroleum resources, various new automotive technologies have been actively developed from the perspective of achieving energy security and diversifying energy sources. Hybrid electric vehicles and electric vehicles are a few such examples. Such diversification requires the use of power control units essentially for power control, power conversion, and power conditioning applications such as variable speed motor drives (dc–ac conversion), dc–dc converters and other similar devices. The power control unit of a hybrid electric vehicle or electric vehicle is essentially the brain of the hybrid system as it manages the power flow between the electric motor generator, battery and gas engine. Over the last few years, the performance of this power control unit has been improved and size has been reduced to attain higher efficiency and performance, causing the heat dissipation as well as heat density to increase significantly. Efforts are constantly being made to reduce this size even further. As a consequence, a better high performance cooler/heat exchanger is required to maintain the active devices temperature within optimum range. Cooling schemes based on multiple parallel channels are a few solutions which have been widely used to dissipate transient and steady concentrated heat loads and can be applied to existing cooling system with minor modifications. The aim of the present study has therefore been to study the various cooling options based on mini-channel and rib-turbulated mini-channel cooling for application in a hybrid electric vehicle and other similar consumer products, and perform a parametric and optimization study on the selected designs. Significant improvements in terms of thermal performance, reduced overall pressure drop, and volume reduction have been shown both experimentally and numerically. This paper is the first part in a two part submission and focuses on the design and evaluation of mini-channel and rib-turbulated mini-channel cooling configurations. The second part of this paper discusses the manufacturing and testing of the cooling device.

Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Schematics of typical (a) Single-sided and (b) Double-sided Power Module [4]

Grahic Jump Location
Fig. 2

Typical heat exchanger used for cooling power control unit of hybrid vehicle

Grahic Jump Location
Fig. 3

Model of the power module package with mini-channel based cooler design. The module consists of the one DBA/DBC substrate layer (∼2 mm total) and one SAC305 solder layer (∼0.1 mm) each for the Silicon IGBT (12.7 mm × 12.7 mm) and diode (10 mm × 10 mm) heat sources. The cooler consists of 11 parallel channels of 1 mm × 1 mm square cross-section in each of the five passes.

Grahic Jump Location
Fig. 4

Temperature contours at the central plane for the power module package with five pass mini-channel based cooler design. Coolant to power module separation (0.5 mm). Arrows indicate the flow direction. Inlet condition: 1 lpm engine coolant at 65 °C. IGBT 1: 403.8 K (130.7 °C), IGBT 2: 405.6 K (132.5 °C), Pressure Drop: 33 kPa.

Grahic Jump Location
Fig. 5

Temperature contours at the central plane for the mini-channel based design having a slightly larger coolant to power module separation (1.5 mm). Arrows indicate the flow direction. Inlet condition: 1 lpm engine coolant at 65 °C. IGBT 1: 406.4 K (133.3 °C), IGBT 2: 407.3 K (134.2 °C), Pressure Drop: 33 kPa.

Grahic Jump Location
Fig. 6

Modified mini-channel based configuration. The cooler consists of sixty-three 1 mm × 1 mm channels—nine in the first pass (first layer), 18 in the second pass (next two layers), 18 in the third pass (next two layers) and 18 in the fourth pass (bottom two layers).

Grahic Jump Location
Fig. 7

Cross-section of a four-pass mini-channels based cooler shown in Fig. 6 with different pressure prediction locations

Grahic Jump Location
Fig. 8

Flow domain in a (a) straight channel, (b) 90 deg ribbed channel, and (c) 45 deg ribbed channel

Grahic Jump Location
Fig. 9

Four different faces of a ribbed channel

Grahic Jump Location
Fig. 10

Temperature contours at the (a) power module package central plane and at the (b) cross-sectional plane at the IGBT 1 center for a cooler based on ribbed mini-channel configuration. All the channels are 1 mm wide × 1.5 mm tall, and only the top seven channels have ribs only on the top surface. Inlet condition: 1 lpm engine coolant at 65 °C, IGBT1: 397.7 K (124.6 °C), IGBT2: 399.4 K (126.3 °C), Pressure Drop: 16 kPa.

Grahic Jump Location
Fig. 11

Temperature contours at the power module package central plane for models based on ribbed mini-channels (a) Model 33. Three flow passes, seven parallel 1.5 mm 90 deg ribbed channels in the first pass, 0.2 mm × 0.2 mm ribs; 2.2 mm pitch, one face ribbed, 14 parallel 1.5 mm channels in the rest. (b) Model 41. Two flow passes, seven parallel 1.5 mm 90 deg ribbed channels in the first pass, 0.1 mm × 0.1 mm ribs; 0.9 mm pitch, one face ribbed, 14 parallel 1.5 mm channels in the next. (c) Model 42. One flow pass, 12 parallel 1.2 mm × 1.5 mm 90 deg ribbed channels in the first pass, 0.1 mm × 0.2 mm ribs; 1.1 mm pitch, all four faces ribbed. Coolant to module bottom surface separation of 1 mm.

Grahic Jump Location
Fig. 12

Variation of Output parameters (channel average HTC and pressure drop) with input parameters (rib angle, rib height, and rib spacing). The channel width refers to the width of the face on which the ribs are present.

Grahic Jump Location
Fig. 13

Sensitivity of the output parameters to the input parameters

Grahic Jump Location
Fig. 14

Smaller conjugate model for ribbed mini-channel based cooler optimization

Grahic Jump Location
Fig. 15

Comparison between the various ribbed mini-channels models

Grahic Jump Location
Fig. 16

Conjugate mini-channel model

Grahic Jump Location
Fig. 17

(a) Inline multilayer mini-channel arrangement with green arrow indicating the flow direction. (b) Staggered multilayer mini-channel arrangement with green arrow indicating the flow direction.

Grahic Jump Location
Fig. 18

Effect of number of layers on the effective heat transfer coefficient for inline and staggered arrangement for two different horizontal offsets (0.25 mm and 1 mm)

Grahic Jump Location
Fig. 19

Multichip power module packaging model based on optimum two layers mini-channel configuration. Flow direction into the plane. Channels are arranged in a staggered manner vertically. All channels have ribs on the top surface.

Grahic Jump Location
Fig. 20

Variation of IGBT temperature as a function of effective heat transfer coefficient under the IGBTs with a 65 °C coolant

Grahic Jump Location
Fig. 21

Multichip power module package model based on optimum two layers one-ribbed wall mini-channel configuration. Single pass flow from left to right in two layers. All channels have ribs on the top surface. Channels are arranged in a staggered manner vertically.

Grahic Jump Location
Fig. 22

Multichip power module package model based on optimum two layers one-ribbed wall mini-channel configuration. Flow direction into the plane. Channels are arranged in a staggered manner vertically. All channels have ribs on the top surface.

Tables

Errata

Discussions

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 eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In