Numerical Simulation Of Heat Transfer In Flexible Wall

Heat transfer enhancement is one of the hot issues in science and engineering technology research field. Heat transfer enhancement can not only realize the efficient use of energy ,and also save energy; but also reduce the volume of equipment under the premise of meeting heat transfer request, and reduce the consumption of materials ,too. In recent years, as the improvement of the energy crisis consciousness and environmental protection consciousness, people pay more and more attention to heat transfer enhancement technology research.At present, heat transfer enhancement technology used in engineering still has some problems. Although heat transfer gets enhanced, increases flow resistance or energy consumption, even the increase of heat transfer effect is far less than the increase of flow resistance and energy consumption. Therefore, in the enhanced heat transfer, we must take into account the flow drag reduction problem, In order to realize energy saving.Study found: special surface in the problem of heat transfer enhancement and flow drag reduction is a feasible method. It is suitable for a wide range, relatively simple in structure and has good prospects for development.This article imposed cyclical fluctuations on the bottom of a rectangular channel in order to simulate the flexible wall. Liquid water is selected as fluid within channel. Dynamic mesh is used in numerical simulation and by using C programmed to import Fluent software, achieved boundary layer girds which is near the channel bottom move with the cyclical fluctuations (degradation, disappearance of reconstruction).In this paper, large eddy simulation is used to the numerical calculation on the flow and heat transfer characteristics of the corrugated rectangular channel. Calculation model is divided into: (1) the amplitude of a = 0.005m, the frequency f = 1Hz; (2) the amplitude of a = 0.005m, the frequency f = 10Hz; (3) the amplitude of a = 0.01m, the frequency f = 1Hz; (4) amplitude a = 0.01m, the frequency f = 10Hz. In addition, this article has also established the rectangular channel with a plane bottom as a benchmark model. And the calculation models and the benchmark model are the same in dimensions, the initial conditions and boundary conditions. The paper compared the numerical simulation results of calculation models with the benchmark model in velocity, pressure, temperature and vorticity; image described the heat transfer characteristics and the flow characteristics in each model. When the numerical calculation of each model reach to steady state, Nu surface friction coefficient and the wall shear stress are recorded in a wave of cycle. Also I analyses the similarities and differences between the change trends of different models, and compare flow characteristics and heat transfer characteristics.In addition, this paper also use the comprehensive evaluation indexes of heat transfer characteristics and flow characteristics to compare the four calculation models with the benchmark model. Finally found the best model.