Evaluation of thermal performance and implementation of prediction tool in a heat exchanger with elliptical leaf strips
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ORIGINAL
Evaluation of thermal performance and implementation of prediction tool in a heat exchanger with elliptical leaf strips J. Bala Bhaskara Rao 1 & J. Siddhartha Yadav 2 Received: 29 May 2019 / Accepted: 30 June 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract In order to enhance thermal efficiency, most process industries are fitted with heat exchangers. Without using external power, we can increase the heat transfer rate by providing different strips in tubes. This paper deals with the passive method of elliptic leaf insertion in a double pipe heat exchanger with opposite orientation and same direction and the heat transfer rate and pressure drop are found. The double elliptical leaf used in experiment has major to minor axes ratios as 2:1 and distance of 50 mm between two leaves are arranged at different angular orientations from 00 to 1800 with 100 intervals. Experimental and numerical simulations are carried and the thermal performance is evaluated at various Reynolds number. Nusselt number increases with increases of Reynolds number and among all elliptical leaf angles, 600 leaf angles gives more heat transfer rate because of high surface area and secondary flows near by the walls of the tube. Friction factor decreases with increased Reynolds number. From the obtained experimental results, a statistical tool generalized regression neural network is considered where the output values are obtained by giving known input parameters without conducting any experimentation. Keywords Nusselt number . Friction factor . Elliptic leaves . GRNN . Accuracy
1 Introduction Heat exchangers play a major role in our day to day life activities. From the geysers which we use early in the morning, cold water in refrigerator to the heater or air conditioners which we use while sleeping all are adjudged to be the offspring of heat exchangers only. Hence, we are surrounded by various heat exchanger devices in daily activity equipment to large industrial applications. Heat exchangers are a major application-oriented heat transfer device where most of the trails are made. It is a great source as a minute change in the equipment produces certain results or a direction of improvement. In this direction there are generally three types of methods which are used Active method, Passive
* J. Bala Bhaskara Rao [email protected] J. Siddhartha Yadav [email protected] 1
Department of Mechanical Engineering, Sri Sivani College of Engineering, Srikakulam, Andhra Pradesh, India
2
Department of Mechanical Engineering, Raghu Engineering College (A), Visakhapatnam, Andhra Pradesh, India
method & Compound methods. In case of active method, the equipment design is changed and different output parameters are found giving rise to a conclusion. Common examples being the change in diameter of the tubes or the shell, increasing or decreasing the number of tubes etc. The passive methods focus on improving the outputs by changing certain parts within the equipment. For example, the flow enhancement of fluid,
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