换热器内自转螺旋扭带除盐防垢研究

传热设备普遍存在不同程度的结垢而导致其传热效果下降,为实现传热管的自动清洗,进行了传热管内自转扰流元件在不同流速下的传热强化及除盐保洁技术的模拟试验研究。依据结晶动力学原理设计模拟试验方案,采用38mm×3mm×2000mm不锈钢管内通NH4Cl热饱和溶液,管外加碳钢套管通冷却水冷却,传热管内分别采用钢丝螺旋结构和塑料扭带进行试验。试验结果表明,在流体雷诺数Re不超过43000的情况下,同等试验条件时,钢丝螺旋结构和塑料扭带在达到平衡时的总传热系数分别比空管提高224%和273%,且塑料扭带除盐效果优于钢丝螺旋结构,可以实现长期连续生产。

Study of salt elimination and scale prevention technology of self-rotating helical twisted tape in heat exchanger

For solving the problem of decreasing heat transfer effect of heat transfer device due to scale buildup,the simulation test study of heat transfer enhancement and salt elimination cleaning technology of self-disturbing flow component inside heat transfer tube at different flow velocities is carried out to realize the automatic cleaning of heat transfer tube.The simulation test scheme is designed according to crystallization kinetics theory.NH4Cl hot saturated solution is passed through the stainless steel tube of φ38 mm × 3 mm(wall thickness)× 2 000 mm(length).The carbon steel casing is added outside the tube to let the cooling water to cool it.And the steel wire helical structure and plastic twisted tape are used inside the heat transfer tube respectively to perform the test.The test result indicates that under the condition of fluid Reynolds number Re less than 43 000,and under the same condition,the total heat transfer coefficients of steel wire helical structure and plastic tache are increased by 224% and 263% respectively compared with hollow tube when reaching the equilibrium state,and in addition,the salt elimination effect of plastic twisted tape is superior to that of steel wire helical structure,therefore,the long-term continuous production can be realized.