间隙支撑换热管的动态特性

Dynamic Response of a Heat Exchange Tube with Motion-Constraint Stops

用数值方法求取了换热管在不同的档板间隙、刚度及激振力下的撞击力及动态响应。对撞击力作等效线性化处理,将间隙支承转化为等效线性弹簧刚度K_(eq)支承。并得出如下结论:(1)K_(eq)和激振力、激振频率、档板间隙有关,等效线性系统的响应和撞击的瞬态响应大体上是一致的;(2)激振力、档板间隙对撞击力起重要作用,但这种影响并不呈线性关系,若间隙进一步增大,则撞击力增长趋势减慢;(3)档板刚度对撞击力影响显著,但对碰撞的瞬态曲线的影响并不明显,减小间隙最终受制造工艺制约,但结构上改变档板刚度是有可能减少磨损的。

Fluid flowing across a tube in a heat exchanger can cause it to impact on the baffles. Employing numerical analysis, the impact force influenced by such factors as clearance, exciting force and frequency has been explored.Applying a technique similar to that for determining Fourier coefficients, namely, multiplying both the impact force and the displacement of contact point by sin ωt and integrating through the whole periodof 2π, the motion-constrained stops can be treated as an equivalent spring. The instanneous response by impact can be represented by response of equivalent system.