The numerical analysis of novel type conic vortex generator and comparison with known VGs for heat transfer enhancement


DEMİRAĞ H. Z. , DOĞAN M. , İĞCİ A. A.

HEAT AND MASS TRANSFER, 2021 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Publication Date: 2021
  • Doi Number: 10.1007/s00231-021-03117-7
  • Title of Journal : HEAT AND MASS TRANSFER
  • Keywords: Heat transfer, Vortex generator, Turbulent flow, Thermal enhancement, Numerical simulation, Channel Flow, SOLAR AIR HEATER, LONGITUDINAL VORTICES, FLOW CHARACTERISTICS, RECTANGULAR CHANNEL, THERMAL PERFORMANCE, CURVED WINGLET, EXCHANGER, AUGMENTATION, OPTIMIZATION, SIMULATION

Abstract

Numerical study was carried out in order to investigate thermo-hydraulic performance and flow characteristics of rectangular channel fitted with the novel type conic vortex generator [NTCVG] in the range of Re = 5000-20,000 with an increment of Re = 2500. To evaluate the NTCVG's effect on heat transfer augmentation, three-dimensional [3D] turbulent flow was analyzed by using the shear-stress transport (SST) k-omega turbulence model. The numerical results revealed that NTCVG was detected to be capable of generating two primary vortices along with four corner vortices for each vortex generator [VG]. NTCVG was compared in terms of TEF with other VGs studied either numerically or experimentally in literature. Due to its curved surface, NTCVG was compared not only with flat surfaced VGs but also with inclined, curved as well as perforated surfaced VGs for the purpose of providing comprehensive comparison. Based on numerical results, NTCVG showed superior performance in comparison to VGs investigated in literature. In terms of heat transfer augmentation, NTCVG manipulates incoming air to the heated surface by its aerodynamically designed shape. The superiority of NTCVG with regard to heat transfer enhancement was exhibited with the use of flow field, temperature and Nu number distribution. DWPC, which performs relatively well in improving heat transfer, was considered for an example of comparison. While both LVGs were determined to be exhibited close f values, an increase in Nu number was attained on the order of 58.75% and 41.05% for NTCVG and DWPC, respectively, in comparison to smooth channel at the lowest Re number. NTCVG showed not only at the rate of 8.42% higher TEF value than DWPC, but also the second highest TEF value [TEFNTCVG = 1.33] was attained among all other VGs compared.