Convection coefficient on a pig body surface based on the surface-model pig

本研究的目的是利用数值分析方法和表面模型猪，对猪体表基于体表形状的对流换热系数进行估算。利用猪的三维外形测量数据，建立了活重分别为27kg、65 kg和88 kg、站立姿势的3头猪的体表模型。曲面模型分别由6598、8838和9304个三角形小块组成，用小块的三维坐标表示。本研究使用这些表面模型代替猪。从连续性方程、运动方程和能量方程出发，模拟了猪体表的空气和热流。在进行三维分析之前，先进行了二维模拟。方程由流函数和涡度以及无因次变量进行变换。然后用有限元法将这些方程转化为离散形式。计算了层流区不同雷诺数和格拉什夫数下猪体表面无因次风速和温度的二维分布。根据空气温度分布估算猪体表对流换热系数。紊流区的系数正在研究中。

The purpose of this study is the estimation of convection heat-transfer coefficient on a pig body surface based on the body shape by using numerical analysis and a surface-model pig.The surface-models of three pigs, which were 27,65 and 88 kg in live weight and in a standing posture, were made by using the data observed from three-dimensional shape measurements of the pigs. The surface-models respectively consisted of 6598,8838 and 9304 triangular patches, and were represented by the three-dimensional coordinates of the patches. These surface-models were used instead of pigs in this study.Air and heat flows on a pig body surface are simulated from the continuity, motion and energy equations. The two-dimensional simulation was investigated before the three-dimensional analysis. The equations were transformed by the stream function and vorticity, and by dimensionless variables. And then these equations were changed to discrete forms by using the finite element method.The two-dimensional distributions of dimensionless air-velocity and air-temperature on the pig body surface were calculated under different Reynolds and Grashof numbers in the laminar flow region. Convection heat-transfer coefficients on the pig body surface were estimated from the air-temperature distributions. The coefficients in the turbulent flow region are under investigation.