41 Electrical Science & Engineering | Volume 01 | Issue 01 | April 2019 Distributed under creative commons license 4.0 DOI: https://doi.org/10.30564/ese.v1i1.1029 Electrical Science & Engineering https://ojs.bilpublishing.com/index.php/ese ARTICLE Validation of Heat Transfer between Theoretical and Experimental from the Internal Surface of Vertical Tubes with Internal Rings Heat- ed by Electrical Heating Coils Ramesh Chandra Nayak 1* Manmatha K. Roul 2 Ipsita jena 3 Ipsita Dash 3 Ashish Ku. Pa- tra 3 1. Mechanical Engineering Department, SVSET, Bhubaneswar, India 2. Mechanical Engineering Department, GITA, Bhubaneswar, Odisha, India 3. Electronics and Telecommunication Engineering, SVSET, Bhubaneswar, Odisha, India ARTICLE INFO ABSTRACT Article history Received: 4 March 2019 Accepted: 12 April 2019 Published Online: 30 April 2019 The comparison between experimental and theoretical heat transfer inside heated vertical channels that dissipate heat from the internal surface with and without internal rings is studied. The experimental setup consists of a circular pipe which is heated electrically by providing constant heat fux on the wall. The theoretical and experimental analysis is conducted in several pipes of same diameter but different lengths. The length of the pipe varies from 450 mm to 850 mm. The length to diameter ratios are taken as L/D = 10, 12.22, 15.56, and 18.89. The value of imposed heat flux varies from 250 to 3340 W/m2. The internal ring thickness varies from 4 mm to 8 mm. separation distance between the internal rings varies from 75mm to 300 mm. The theoretical results are compared with experi- mental data to ascertain numerical accuracy of the method. The effects of L/D ratio, thickness of internal rings and separation distance on the heat transfer performance are studied. The experimental result is compared with theoretical, theoretical results are found by using ANSYS. In this study theoretical result for wall temperature along the height of tube, fuid temperature at exit of tube are compared with experimental data. Keywords: Heat transfer Natural convection Protrusion thickness Separation distance Geometrical sizes *Corresponding Author: Ramesh Chandra Nayak, Mechanical Engineering Department, SVSET, Bhubaneswar, India; Email: rameshnayak23@gmail.com 1. Introduction N atural convection heat transfer is an exclusive and cost-effective cooling method adopted by electronic industry in order to cool the high voltage electric devices as well as dissipate the heat from the electronic devices or modules which are embedded on a small base. Heat transfer denotes to the transfer of energy taking place in temperature between them. This energy transfer is known as heat. It is known that heat transfer takes place in three modes i.e. conduction, con- vection and radiation. It is a known fact that a hot plate of metal cools fast- er when placed in front of a fan than in front of still air. Thus it can be said that that heat is convected away from the source and this process is called convection heat transfer. It occurs by means of two processes either by forced convection or by natural convection. Forced