多孔氧化铝陶瓷内高温流体的流动及传热特性

通过仿真模拟的方法研究了模拟烟气、水蒸气及含尘烟气三类高温流体在多孔氧化铝陶瓷材料内的流动及传热特性。结果表明:随孔隙率增大，流体平均流速加快，流体进出口温降逐渐减小。三类流体中，水蒸气流速最大，在最大孔隙率下其流速达到66.64 m/s；烟气温降最显著，当孔隙率为0.3时，其进出口温差达到最大值85.6 K。随压差的增大，流体流速加快，其中受粉煤灰颗粒影响的含尘烟气流速增幅较小，流速仅从0.23 m/s增至0.93 m/s；另一方面，压差增大导致流体与壁面的热传导减少，模型内流体温降减小。含尘烟气流体扰动较大，当增大孔隙率和压差时，流速呈线性增长；尽管粉煤灰颗粒的存在强化了传热，但流体分子间的相互作用使得含尘烟气温度变化显著。

Flow and Heat Transfer Characteristics of High Temperature Fluids in Porous Alumina Ceramics

The flow and heat transfer characteristics of simulated flue gas, water vapor and dust-laden flue gas in porous alumina ceramic materials are studied by means of simulation in this paper. The results show that with the average fluid velocity increases, and the temperature drop at the inlet and outlet of the fluid decreases gradually with the increase of porosity. The water vapor velocity is the largest in among these three types of fluids, and its velocity reaches 66.64 m/s at the maximum porosity; the flue gas temperature drop is the most significant, when the porosity is 0.3, the temperature difference between inlet and outlet reaches the maximum value of 85.6 K. With the increase of the pressure difference, the fluid flow rate increases, and the flow rate of the dust-laden flue gas is slightly affected by the fly ash particles increases, and the flow rate only increases from 0.23 m/s to 0.93 m/s; on the other hand, the increase of the pressure difference caused by heat conduction between the fluid and the wall is reduced, and the temperature drop of the fluid in the model is also reduced. The fluid disturbance of dust-laden flue gas is relatively larger, and the flow velocity increases linearly with the increase of porosity and pressure difference; however, the presence of fly ash particles enhances heat transfer, but the interaction between fluid molecules makes the temperature of dust-laden flue gas changes significantly.