Experimental and numerical investigations on the effects of insertion-type longitudinal vortex generators on flow and heat transfer characteristics in square minichannels

• Published in: Energy (Oxford) Vol. 278; p. 127855
• Main Authors: Feng, Zhenfei, Jiang, Ping, Zheng, Siyao, Zhang, Qingyuan, Chen, Zhen, Guo, Fangwen, Zhang, Jinxin
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2023
• Subjects: Heat transfer enhancement; Longitudinal vortex generator; Minichannel heat sink; Thermal-hydraulic characteristics; Heat transfer enhancement; Thermal-hydraulic characteristics; Minichannel heat sink; Longitudinal vortex generator
• ISSN: 0360-5442
• DOI: 10.1016/j.energy.2023.127855

Longitudinal vortex generator (LVG) is an effective device for enhancing heat transfer in micro/mini-channel thermal systems. In this study, a new insertion-type LVG (ITLVG) is designed and the effects of length and arrangement of ITLVG on flow and heat transfer characteristics in square minichannel are explored using experimental and numerical methods under Reynolds number of 414–1042. Results show that the vortex flow is generated in both sides of ITLVG and behind ITLVG, thereby intensifying flow disturbance and reducing the thermal boundary layer. The friction factors and Nusselt numbers in the minichannels with ITLVGs increase by 85.5%–246.1% and 39.2%–102.0% on average, respectively, compared to smooth minichannel. The ITLVG arrangement has a significant effect on the flow and heat transfer, while the ITLVG length has a slight effect. The ITLVG with the length of 20 mm and arranged simultaneously in upstream, midstream and downstream shows the highest performance evaluation criterion (PEC) values at most of Reynolds numbers, as well as maximum PEC value reaches 1.50 at the Reynolds number of 1042. Moreover, the correlations for Nusselt number and friction factor are developed. Overall, the new ITLVG performs beneficial effect for comprehensive performance improvement in minichannel to increase energy conversion efficiency. •A novel insertion-type longitudinal vortex generator is designed.•Effects of this vortex generator on performances in minichannel are studied.•Friction factors with this vortex generator are increased by 85.5%–246.1%.•Nusselt numbers with this vortex generator are increased by 39.2%–102.0%.•The highest performance evaluation criterion value reaches 1.50.