Large Eddy Simulation Of Fluid Flow And Heat Transfer In Narrow Rectangular Channel In Rolling Motion

When the ship is sailing in the ocean, the fluid flow and heat transfercharacteristics of ship power equipments are influenced by the periodic additionalinertia force produced from the rolling motion, and thus the power systems areinfluenced. Hence it is important to study the fluid flow and heat transfer characteristicsof this kind of coolant channel. In the paper, the three dimensional unsteady fluid flowand heat transfer in narrow rectangular channel is simulated by large eddy simulationmethod, to investigate the influences of rolling motion on fluid flow and heat transfercharacteristics.In order to validate the subgrid model and to analyze the turbulence characteristicsof the narrow rectangular channel, the turbulence statistics, including wall law,Reynolds stress, RMS velocity, were analyzed, the influences of rolling motion on theRMS velocity and Reynolds stress were studied. We found that DSLM has a goodagreement with Spalding curve in the viscous sublayer, but it is higher in thelogarithmic region; The peak of v_rms⁺is farther away from the wall than the one of u_rms⁺and w_rms⁺in the rolling motion, and the peak of w_rms⁺and Reynolds stress relocatesignificantly, which certifies that the rolling motion inhibits the turbulence.The transient velocity and temperature field in the narrow rectangular channel wereanalyzed, we grasp the characteristics of spatial distribution, time change and vorticesdistribution in the boundary of the transient flow field; The results of different rollingperiods, rolling amplitude and Reynolds number were compared, and the variation ofthe friction pressure drop in different rolling periods, rolling amplitude and Reynoldsnumber was analyzed, the different performance of friction coefficient and Nusseltnumber in rolling motion and non-rolling motion were mechanism analyzed deeply.Finally, the correction of single-phase fluid friction coefficient and Nusselt number ofnarrow rectangular channel were propposed, The proposed correction can well predictthe experimental data and numerical simulation data.