Passive enhancement of heat transfer in a microchannel by an adjoint system of cylinder and flexible beam

Abstract

Based on passive heat and mass transfer enhancement technology, a control method combining a cylindrical obstacle and a flexible beam was proposed to improve heat transfer performance in a microchannel. The optimal layout of a flexible beam was investigated under varying inclination angles of the beam and its spacing distances to the cylindrical obstacle through two-dimensional simulations of heat transfer, fluid and solid interaction. The control mechanism of the flexible beam was qualitatively analyzed from views of flow pattern and structural vibration. It was found that the pressure loss and heat flux should be considered simultaneously, to achieve the best performance of the heat transfer. Results showed that optimal performance occurred when the inclination angle of the beam and its spacing distance to the cylinder took specific values. In such circumstances, the flexible beam’s vibration was amplified by the periodic vortex shedding from the upstream cylinder, without introducing too large a blocking effect. The appropriate control strategy of fluid-structure interaction can enhance the disturbance of the thermal boundary layer and result in the largest thermal enhancement factor.

Keywords:

• Active control
• energy efficiency
• flow pattern
• fluid-solid interaction
• vortex-induced vibration

Additional information

Funding

This work was supported by the National Natural Science Foundation of China #1 under Grant Number 11872174, Fundamental Research Funds for the Central Universities #2 under Grant Number B200202236, 111 Project #3 under Grant Number B18062, and Key Laboratory of Port; and Waterway & Sedimentation Engineering Ministry of Communications PRC #4 under Grant Number Yk220001-2.