Heat transfer characteristics of hot surface by synthetic JET impingement

Abstract

The present dissertation reports the experimental and numerical investigations pertaining to the flow and heat transfer behavior of synthetic jets (SJs). The objective of the present study is to analyze the thermal performance of SJs for varied range of geometrical and operating parameters as applicable to various industrial applications, including the thermal management of electronic components. A test facility has been developed that include various modules, such as test specimen, power supply system, SJ module, traversing mechanism, and instrumentation scheme for temperature and velocity measurement. A matt finish SS-304 foil of 0.05 mm thickness has been used as the test specimen and heated by employing a DC power (Aplab 3260) supply system. The voltage drop and current supply through the foil is measured by using a digital multimeter (Fluke 287, True-rms multimeter); the temperature distribution over the test surface is recorded by using an infrared thermal imaging camera (FLIR A655sc). The SJ cavity is designed by using an electromagnetic speaker (Visaton FRS 7s). The input power to the actuator is provided by using an amplifier (Ahuja DPA 370 and Syscon SI 28); while, the function generator (Tektronix AFG1022) and oscilloscope (Tektronix TBS1072B) is used to vary the excitation frequency and monitor the input signal to the speaker, respectively. A constant temperature hot-wire anemometer (Dantec dynamics Mini CTA 54T42) is used to measure the jet velocity. Here, tests are performed for a varied range of Reynolds numbers (1183-5448), jet-to-surface spacing (0-30), orifice shapes (circular, square, rectangular with varied aspect ratio), and various orifice thicknesses (1.6-5mm).