声空化污水换热器的防除垢与强化换热实验

Experiment on the antiscale and descaling and heat transfer enhancement of acoustic cavitation sewage heat exchanger

摘要:

为解决污水源热泵系统中污水换热器结垢导致的热阻增大、传热效果恶化问题，将声空化技术引入污水换热器中.搭建声空化污水换热器的防除垢与强化换热动态实验台，研究防除垢与强化换热的数学模型，对不同影响参数下污水换热器换热管的污垢增长特性和防除垢规律以及强化换热效果开展实验研究.结果表明：换热管结垢量、结垢率、积垢速率及污垢厚度均随污水流速的降低而增大，最大结垢量为106 g，结垢厚度0.54 mm，积垢速率为12.6 kg/(m²· h)；除垢率随流速及声空化作用时间的增大而增大，但非一直增大，最大除垢率达85.7%；污水黏度对各项指标影响巨大且流速越小影响越大；换热管的传热系数及其提高百分比均随声空化作用时间、污水温度以及污垢含水率的增加而增大，最大提高百分比达53.4%.故声空化污水换热器防除垢与强化换热具有一定的可行性和高效性，对节能减排具有重要意义.

Abstract:

The scaling of sewage heat exchanger in sewage source heat pump system leads to increase of thermal resistance and decrease of heat transfer effect. In order to solve these problems, the acoustic cavitation technology was introduced into sewage heat exchanger. The dynamic experiment table of antiscale & descaling and heat transfer enhancement by acoustic cavitation sewage heat exchanger was established. Mathematical models of acoustic cavitation antiscale & descaling and heat transfer enhancement were analyzed. The fouling growth characteristics, and the law of antiscale & descaling and heat transfer enhancement effect of sewage heat exchanger tubes under different influence parameters were researched. The results are as follows. The amount of scale, scaling rate, fouling rate and fouling thickness of heat exchanger tubes are increased with the decrease of sewage flow velocity. The largest amount of scaling is 106 g, fouling thickness is 0.54 mm, and fouling rate is 12.6 kg/(m²· h). Descaling rate increased with the increase of flow velocity and acoustic cavitation action time, and the largest descaling rate is 85.7%. Sewage viscosity has a huge impact on the various indexes and has greater influence with the smaller velocity. Heat transfer coefficient and its enhanced percentage are increased with the increase of acoustic cavitation action time, temperature of sewage and fouling moisture rate, and in addition, the percentage of heat transfer coefficient runs up to 53.4%. So the antiscale & descaling and heat transfer enhancement of acoustic cavitation sewage heat exchanger have a certain feasibility and high efficiency, and great significance to energy conservation and emissions reduction.