Thermographic Evaluation of Forced Convective Heat Transfer Coefficient at University of Ancona

Table of Contents

Introduction
New Cooling Methods for Electronic Components
Experimental Set-Up
Infrared: for Fast and Accurate Results
Conclusion
About FLIR

Introduction

Infrared thermography, a non-contact and non-invasive technique for temperature measurement, provides superior results with a very minimal experimental set-up. This is one of the many reasons for which a FLIR Systems ThermaCAM is being utilized by the University of Ancona in its research programs. This article discusses the application of a FLIR Systems ThermaCAM in thermographic evaluation of the forced convective heat transfer coefficient of liquid-cooled short pin fins at the University of Ancona.

New Cooling Methods for Electronic Components

Improved heat transfer surfaces with short pin fins are often used in various engineering fields such as in gas turbine blades cooling and in microelectronic applications. In these applications, the most widely utilized cooling element is the air. Systems based on these types of heat removal technologies ensure good thermal performances in these applications. However, the air-cooling technique is not capable of ensuring the thermal control for the specific thermal flux in the range between 50 and 100 W/cm2 generated by the components. The closed loop liquid cooled systems that normally use the water as the working fluid is a better option in these cases. This technology may be used in telecommunications equipment and in advanced desktop computers.

Experimental Set-Up

Figure 1. The set-up for the study with the FLIR Systems ThermaCAM

The objective of the research, through infrared temperature measurements, is to measure liquid-cooled short pin fins’ forced convective heat transfer coefficients in single, staggered, in line pin arrangements. The research results may be utilized for cold plate heat exchanger design for dissipating the heat flux produced by power electronic components.

The analysis includes four pin shapes, namely triangular, square, circular, and rhomboidal, in single and in line arrya configurations. The experimental apparatus comprises a closed liquid loop to provide a test section where the improved heat transfer surfaces are added. The test section’s one side is equipped with an infrared window to observe the pin tip temperature with a FLIR Systems IR camera.

Infrared: for Fast and Accurate Results

Figure 2. Professor Ricci holding one of the cold plate heat exchangers

Prof. Renato Ricci reported that the selection of the IR technique enables to make more rapid and precise thermal measurements without inserting thermocouples into the pins. Moreover, infrared provides real time responses thanks to its quicker experimental set-up. Naphthalene sublimation is another method widely utilized for the evaluation of the convective heat transfer coefficient in short fins. However, the technique is relatively complex for industrial tests and consumes more time to retrieve a large set of experimental data. Since the infrared camera is able to observe even a slight change in temperatures, the results provided by utilizing a FLIR Systems ThermaCAM are in line with those provided by other techniques and other authors.

Figure 3. Infrared images of the tested pin shapes

Conclusion

Extensive ink flow visualizations were performed for each shape of the pins in order to provide new insights into the thermal and fluid dynamic characteristics of the fins. At present, other configurations and pin shapes are being tested with a special focus on the telecommunications applications.

About FLIR

FLIR was founded in 1978, originally providing infrared imaging systems that were installed on vehicles for use in conducting energy audits. Later, we expanded our focus to other applications and markets for our technology, in particular, designing and selling stabilized thermal imaging systems for aircraft used by law enforcement. We have since grown substantially due to increasing demand for infrared products across a growing number of markets combined with the execution of a series of acquisitions. Today we are one of the world leaders in the design, manufacture and marketing of thermal imaging and stabilized camera systems for a wide variety of applications in the commercial, industrial and government markets, internationally as well as domestically.

Our Thermography business primarily consists of the design and manufacture of hand-held thermal imaging systems that can detect and measure minute temperature differences, which are useful for a wide variety of industrial and commercial applications. Uses for our Thermography products include high-end predictive and preventative maintenance, research and development, test and measurement, leak detection and scientific analysis. A growing distribution network has enabled us to penetrate existing and emerging markets and applications worldwide.

This information has been sourced, reviewed and adapted from materials provided by FLIR.

For more information on this source, please visit FLIR.

Date Added: Nov 29, 2012 | Updated: Jun 11, 2013
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