76 / 2025-04-15 20:08:09

Thermal physiological model construction and heat stress evaluation of dairy cows in CFD virtual wind tunnel

CFD simulation,hermophysiological responsiveness

3. 智慧牧场与动物福利 > （4）智慧牧场应用的案例实践

The thermal state of dairy cows is mainly based on the level of their heat production and dissipation. However, environmental parameters are the basis through which the thermal environment assessment method based on computational fluid dynamics (CFD) indirectly calculates the thermal comfort of dairy cows. This indirect method may lead to unclear and inaccurate results. The main purpose of this study is to build a digital model integrating thermal physiological characteristics of dairy cows in a CFD virtual wind tunnel. By directly coupling the thermal regulation mechanism of dairy cows with environmental flow field parameters, the simulation accuracy can be improved and the thermal comfort state of dairy cows can be visually and accurately reflected. A virtual dairy cow with thermophysiological responsiveness was constructed by establishing a three-dimensional geometric model of dairy cow and implanting a three-layer thermal regulation mechanism model of "metabolic heat production - sensible and latent heat distribution - skin surface heat transfer". In addition, the mapping relationship between skin temperature index (STIC), effective temperature index (ETI) and temperature and humidity index (THI) of dairy cows and heat yield/heat dissipation of virtual dairy cows under typical thermal conditions was compared. The results show that the inclusion of virtual cows in CFD simulation can more sensitively and intuitively reflect the thermal comfort state of cows. THI exhibited a stronger linear correlation with the virtual cow's heat production/dissipation than STIC and ETI, but virtual cows significantly increase the number of grid cells in the simulation.