烟气输运和水喷淋相互作用的大涡模拟研究

摘要

Smoke movement with a water spray is investigated by large eddy simulation (LES) technique. The filtered three-dimensional compressible Navier-Stokes equations under low-Mach-number approximation and the species equation are numerically solved. The motion of smoke is driven by Lagrangian particles (thermal elements) carrying the heat release of combustion, and a water spray ejected from a sprinkler is simulated. Thermal turbulent flow induced by an isolated pool fire in a two-wall enclosure with and without the water spray is discussed. Interaction of the water spray with the smoke as well as the cooling of hot gases by the water spray are investigated for different water spray angles and spray droplet sizes.%本文应用大涡模拟方法,并结合Smagorinsky 亚格子尺度模型,数值研究了烟气输运和水喷淋的相互作用问题.为了有效地模拟烟气输运过程,文中采用低马赫数近似下的三维可压缩Navier-Stokes方程和组分方程进行求解,并采用有限差分法数值计算了滤波后的控制方程.对于燃烧过程中所产生的热释放,采用Lagrangian粒子携带热量的近似方法来模拟,这些运动粒子进一步用来标识烟气的输运过程,同时还近似模拟了水喷淋和热气流的相互作用过程.文中数值计算了燃烧火源所形成的热气流和烟气输运过程,以及与水喷淋的相互作用,并探讨了喷水装置的喷水量、喷射角和水颗粒直径对流动特性的影响.