Experimental Investigation of the Effects of Ring Turbulators on Heat Transfer in Two-Phase Flow

Studies that have been conducted in the field of Fluid Mechanics have shown that two-phase flows are preferred more over single-phase flows as their heat transfer coefficient is higher. In this study, it was aimed to experimentally investigate the effects of a ring-shaped series as a pipe part towards eliminating negative situations in two-phase flow systems. In the experimental study, the test setup consists of a two-phase flow system with forced convection boiling inside a straight horizontal pipe with an internal diameter of 17.6 mm and an external diameter of 25 mm. A heat transfer surface configuration was used during the experiments. In the system, the effects of the part consisting of series of rings as an in-pipe heat transfer improvement element on the flow instabilities were investigated. By selecting the fluid input variable flow rate as a parameter, the effects created by series of rings were examined in constant operational pressure, constant input temperature, constant thermal power and exit limiter conditions. Additionally, the wall temperatures of the pipes and pressure-flow rate changes were examined. According to the results of the experimental study, it was observed that the temperature limits of the "burn-out" forming in the surface-increased test pipe were highly reduced in comparison to the empty pipe. It was determined that, with this, damages to be incurred on the pipe walls were reduced. Moreover, it was observed that, at a certain mass flow rate, as the thermal power increased, the pressure drops also increased. Between the two different pipes that were used, the pipe with the high-pressure drop was the surface-increased pipe. This study aims to examine the experimental effects of ring turbulators as pipe elements in addition to the previously studied turbulator types for eliminating the negative effects in two-phase flow systems. As a result of the experiments, it was observed that the pressure drop increased with the increase of the thermal power at a certain mass flow. Previously used heat transfer when compared with the test results with surface elements, in the two different pipes used, the pipe with a high drop in the pressure was the Pipe-2.

Journal

IRANIAN JOURNAL OF SCIENCE AND TECHNOLOGY-TRANSACTIONS OF MECHANICAL ENGINEERING

Year

2022

Volume

46

Issue

3

Pages

829-838

ISSN

2228-6187

eISSN

2364-1835

DOI

10.1007/s40997-021-00472-y

WoS UID

WOS:000720809800001