Experimental Investigation of Inclined Circular Ring Turbulators on Heat Transfer and Fluid Flow Characteristics

Abstract

This paper demonstrates influence of various inclination of Circular Ring Turbulator (CRT) on thermal characteristics in circular type heat exchanger. “A wall linked circular inserts were analyzed having constant inner diameter to achieve uniform flow blockage area (FBA) of 40%”. These CRTs located within the tube to prevailed different angular patterns (-10°, -15°, - 20° and -25°) w. r. t. horizontal of tube. Influence of these geometries on fluid friction and heat performance were studied. Parameter constant throughout the investigation was diameter ratio and Pitch Diameter Ratio (PDR). Modified parameters throughout study were the angular inclinations of CRT and Reynolds number. Inner side of tube is preserved at constant heat flux having air as working medium at atmospheric temperature with variation of Reynolds number from 6,000 to 24,000 respectively. Implementation of CRT as turbulator favorably improves rate of heat exchange within heated enclosure of tube to fluid domain throughout the test model. Out of all studied inserts, CRT having angular deflection of -25° gives peak value of heat transfer at extreme Reynolds number and at slightest Reynolds number CRT having angle inclination of -10° offers greater friction factor which is at 2.5 and 5.5 times than smooth tube. CRT with angular inclination of -25° at minimum Reynolds number offers extreme thermal performance factor is 1.7.

Investigation of heat transfer augmentation in a horizontal tube using different rectangular cut ring inserts

“…The convective heat transfer rate between a heated wall and a flowing fluid greatly affects the thermal performance of the heat-exchanging devices. 1,2 For enhancing the convective heat transfer and lowering the loss of pressure across the heat exchanger, it is possible to decrease the size and cost of the heat-exchanging device besides the amount of energy that must be pumped. The convective heat transfer rate is accelerated and improved by increasing the turbulence, restricting and blocking the fluid flow, as well as by creating a swirl by changing the surfaces.…”

“…It was concluded that the installed tube inserts in the heat exchanger tube led to a significant increase in Nu number and energy saving. Chamoli et al 11 developed perforated vortex generators with three relative pitch lengths (2,4,6) and four distinct perforation indices (4%, 8%, 12%, and 16%) to enhance the convective heat transmission. The main results showed that the thermal enhancement factor increased as the perforation indexes increased, but the heat transfer and pressure drop increased as the perforation indexes decreased and the pitch lengths increased.…”

“…The convective heat transfer rate between a heated wall and a flowing fluid greatly affects the thermal performance of the heat‐exchanging devices 1,2 . For enhancing the convective heat transfer and lowering the loss of pressure across the heat exchanger, it is possible to decrease the size and cost of the heat‐exchanging device besides the amount of energy that must be pumped.…”

“…Suryavanshi et al 2 illustrated the effects of different circular ring turbulators (CRTs) with a uniform FBA of 40% and inclinations of different angular patterns (−10°, −15°, − 20°, and −25°) on the thermal properties of circular type heat exchangers. With air serving as the working medium and the Reynolds number varying from 6000 to 24,000, the inner side of the tube is maintained at a constant heat flux.…”