Numerical Study of Heat Transfer in a Lattice Matrix with Varying the Crossing Angle

The development of methods for intensifying heat transfer is a priority task in various technological processes in the energy sector and aerospace engineering. One of the effective ways to enhance heat transfer is to install mutually intersecting ribs on opposite walls of the channels (vortex matrices or latticework). The use of such channels leads to formation of a complex three-dimensional turbulent flow, which contributes to a significant enhancement of heat transfer. Most of available literature publications deal with the study of the integral characteristics of hydraulic losses and the degree of heat transfer enhancement depending on a large number of defining parameters. At that, the local flow structure and heat transfer have not been fully investigated. In particular, this conclusion relates to understanding the mechanism of the flow from subchannels formed by parallel ribs on opposite walls and interaction of these flows with the lateral bounding walls of the latticework. In this work, the main attention is paid to the study of the flow processes without the influence of the side walls of the channel. The results of numerical calculations of separated turbulent flow in a latticework obtained using the RANS and LES methods and the OpenFOAM package are presented here. Calculations were performed for the angles of rib crossing 2 beta = 60 divided by 120 on opposite heat transfer surfaces and the Reynolds number Re = 5, 000 divided by 15, 000, determined from the average flow rate and channel height. Data on the flow structure in a cell of a latticework were obtained. It is shown how the angle of crossing affects the interaction of flows in the lower and upper subchannels. The distribution of local heat transfer on the channel wall and the dependence of the average Nusselt number on the angle of crossing and the Reynolds number were obtained.