25-08-2017, 09:32 PM
Abstracts: We worked with the “MAZDA LIMITED” which is located at Ahmedabad. They mainly manufacture “Heat Exchangers” and “Ejectors”. A heat exchanger is a device in which energy is transferred from one fluid to another across a solid surface. A shell and tube heat exchanger is a class of heat exchanger designs. It is the most common type of heat exchanger in oil refineries and other large chemical processes, and is suited for higher-pressure applications. As its name implies, this type of heat exchanger consists of a shell (a large pressure vessel) with a bundle of tubes inside it. One fluid runs through the tubes, and another fluid flows over the tubes (through the shell) to transfer heat between the two fluids. High-intensity ultrasound can induce cavitation bubbles and acoustic streaming in liquid, which makes it possible for power ultrasonic to be applied to the improvement of heat transfer process. In the present work, the experimental study was made on the heat transfer enhancement of water-water heat exchanger in shell-and-tube type assisted by power ultrasonic. The design of the experimental system is presented in detail, and the experimental procedures is expounded as well to make the study process more clearly. The acoustic frequency of ultrasound transducer employed is about 21 kHz, and three power levels (40W, 60W and 100W) are used for this study. The impact of water flow rate and inlet water temperature in the tube as well as the ultrasonic power on the enhancement were investigated. It was found that the water flow rate and ultrasonic power levels would produce great influence on the enhancement by power ultrasound which decreased with the increasing water velocity in the tube and the decreasing acoustic power.