Conical Spring Inserts Effect on the Thermo- hydraulic Characteristics in Circular Copper Tube

Abstract

Experimental and numerical investigation was conducted to study the thermo-hydraulic characteristics in circular tube fitted with conical spring inserts. The dimensions of circular copper tube are 100cm, 2.2cm and 2.4 cm which represent the length, inner and outer diameters respectively. The length of insert was 15cm, while the conical spring has 16mm diameter gradually decreases to 6mm with the length and the pitch between the coils was 20mm. The diameter of wire used to fabricate the conical spring insert was 4mm. Those inserts were arranged into eight categories (A1 to A8). In the numerical part, the governing equations were solved by using commercial ANSYS-Fluent package (2019 R3) with the assistance of solid works and Gambit software program. The finite volume approach was used in solving the equations to predict the pressure flow, heat transfer and temperature distribution along the tube. Experimental work included design and built a test platform for the experimental measurements. The aim of experimental study was to predict the behavior of heat transfer and pressure in the tube with two cases, plain tube and inserted tube at the effect of different parameters. All experimental tests were conducted at turbulent flow fully developed. The range of Reynolds number and heat flux were (3542-7522) (4549-10576 W/m^2) respectively. The results showed that the best augmentation in heat transfer was by using a category A5 of conical spring insert compared with plain tube. Results show good agreement between the numerical and experimental results with an error of 8%. Also results showed that the Nusselt number increases as the Reynolds number increasing.