陶瓷过滤管内外流场的数值模拟

Numerical Simulation of Flowfield in Ceramic Filter Candle During Pulse-Backing Cleaning

将陶瓷过滤管内流场假设为二维、轴对称、可压缩、非稳态的湍流流场 ,采用k -ε模型 ,并将能量方程与流动控制方程联立计算 ,模拟脉冲反吹过程中滤管内速度场和温度场。通过对湍流控制方程无量纲化和坐标变换后 ,用隐式格式求解 ,并对每次的迭代结果进行附加的光滑化处理。数值模拟结果证明了滤管内外存在着严重的回流现象 ,滤管外回流峰值可以达到正常过滤气速的数倍。管外壁面附近的径向速度随着离开壁面距离的增加而逐渐减小 。

The flow-field inside ceramic tube is regarded as two-dimensional, unsteady, compressible and axis-symmetrical, the velocity and temperature flow-fields inside ceramic filter candle during pulse-backing cleaning was simulated by adopting a standard k-ε model and solving the system of energy equation and flow control equation. After making the turbulent current control equation dimensionless and using the coordinate exchange, the calculation was carried out by implicit iteration, and the calculation results of iteration was also with extra smooth processing. The result shows that there exists a remarkable back-flow phenomena both in and out ceramic tube during pulse-jet cleaning. The peak value of reflex outside the tube can be several times of normal jet velocity. The radical velocity outside tube decreases as the distance to tube wall increases. The result provides a theoretical basis for optimum designing pulse-backing cleaning system.