Thermal Performance Evaluation of a Tubular Heat Exchanger Fitted with Combined Basket–Twisted Tape Inserts

Applied Sciences

卷:12

Hayder Q. A. Khafaji¹  Wisam Abed Kattea Al-Maliki²  Hasanain A. Abdul Wahhab²  Sajda S. Alsaedi²  Falah Alobaid³  Bernd Epple³ 

[1] Department of Electromechanical Engineering, University of Technology-Iraq, Baghdad 19006, Iraq;

[2] Mechanical Engineering Department, University of Technology-Iraq, Baghdad 19006, Iraq;

[3] TU Darmstadt, Institut Energiesysteme und Energietechnik, Otto-Berndt-Straße 2, 64287 Darmstadt, Germany;

关键词: heat transfer enhancement;    binary basket–twisted strip inserts;    friction characteristics;    thermal performance characteristics;    turbulent flow;   

DOI  :  10.3390/app12104807

来源: DOAJ

【 摘 要 】

Features of the tubular type of heat exchanger were examined experimentally in the current study. A rig is fitted with a novel insert as a negative heat transfer increase technique. The core fluid used is air under steady heat flux and a turbulent discharge state (6000 ≤ Re ≤ 19,500) conditions. Two heat transfer augmentation inserts are employed; one is the basket turbulators utilized as a turbulator and placed inside the heat exchanger with a constant pitch ratio (PR = 150 mm), and the other is the basket turbulators together with twisted tape that are installed at the core of the basket turbulators. The measurements illustrated that the Nusselt number (Nu) was found to be higher by about 131.8%, 169.5%, 187.7%, and 206.5% in comparison with the plain heat exchanger for basket turbulators and the combined basket–twisted tape inserts with y/w = 6, 3, and 2, respectively. The highest thermal efficiency factor of the increased tubular heat exchanger is 1.63 times more elevated than that of the simple heat exchanger on average, due to a binary basket-quirky strip for a twisting percentage y/w equal to 2 under steady pumping energy. Further, practical correlations for the Nusselt number, as well as friction characteristics, were established and presented.

【 授权许可】

Unknown