Experimental Study of The Effects of Fluid Flow and Heat Transfer on Vibration Induced by Water Flow in Straight Pipe with Orifice
Salah H. Abid Aun†, Safaa A. Ghadhban‡, Kadhum A. Jehhef †
† Middle Technical University, Institute of Technology- Baghdad, Iraq.
‡ Middle Technical University, Electrical Engineering Technical College- Baghdad, Iraq.
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This paper attempts to study the effects of induced vibration on characteristics of fluid flow and heat transfer. The fluid vortex-induced vibration caused by an orifice has been studied experimentally. The orifice is used as vortex generator inserted in a simply supported circular pipe that conveying water in turbulent flow condition. The pipe diameter is 20 mm and its length is 1500 mm. The experiments are conducted for four orifice aspect ratios; 0.15, 0.3, 0.45 and 0.6. The flow rate is regulated such that Reynolds number (Re) is from 5500 to 11000. The water inlet temperatures are varied from 20o to 60o C. The time history signals of the structure vibration accelerations are measured by the accelerometer. The experimental results are given by natural frequency parameters of the free vibration signals of the pipe structure. The results show that using an orifice increases the pipe frequency parameters such as acceleration, velocity and displacement. In addition, these vibration fundamental parameters increase with increasing Re as well as water inlet temperatures. The frequency is the highest value at the case of low aspect ratio of orifice. Furthermore, the Nusselt number increases with increasing the Re and with decreasing the orifice aspect ratios for all conditions.