Enhancing convective heat transfer based on minimum power consumption principle

Equation of power consumption in the flow process of micro-fluid elements has been deduced in this paper by analyzing the mechanical energy equilibrium equation of microelement based on the stress relation of Newtonian fluid. By setting minimum power consumption as optimization objective and entransy consumption as constraint condition, optimization flow field equation for convective heat transfer on the basis of energy conservation equation and continuity equation are constructed. Numerical investigations of forced convective heat transfer in a circular tube based on the optimized controlling equations are conducted, and the results show that there are multi-longitude-vortexes existing in velocity field, which leads to an enhancement of heat transfer. The analysis for the heat transfer and flow resistance shows that this kind of flow field accommodates a far greater heat transfer increase than flow resistance increase, which proves that the proposed optimization theory is effective in designing high efficient heat transfer enhancement unit.

► Minimum power consumption principle is proposed to find optimal flow field.
► Numerical solution of optimal flow field is obtained.
► Heat transfer is enhanced by achieving such an optimal flow field.