U形污水換熱管中顆粒污垢沉積特性研究
Study on deposition characteristics of particulate fouling in U-shaped sewage heat exchange tubes
摘要：
分析了不同污水流速、污水黏度、顆粒濃度及顆粒粒徑下顆粒污垢在換熱壁面上的沉積、剝蝕及熱阻的變化情況。結果表明：污水的流速、黏度及顆粒的濃度對顆粒污垢的沉積情況影響較大，在其他參數不變的情況下，當流速由0.5 m/s增大到1.5 m/s時，沉積速率增大了2.3 倍，剝蝕達到穩定的時間縮短為原來的1/6，污垢熱阻減小56%；當污水的黏度由0.001 0 Pa·s增大到0.003 0 Pa·s時，剝蝕達到穩定的時間延長1.27倍，污垢熱阻增大1.25倍；當顆粒濃度由400 mg/L增大到800 mg/L時，剝蝕達到穩定的時間增加約1倍，污垢熱阻增大約1倍；顆粒粒徑對污垢沉積特性的影響較小，當顆粒粒徑由1 μm增大到40 μm時，沉積速率僅增大14%，污垢熱阻僅增加12.8%。研究結果可供污水換熱器設計、運行及除垢參考。
Abstract：
This paper analyses the changes of deposition, denudation and thermal resistance of particulate fouling on the heat exchange wall under different sewage flow rate, sewage viscosity, particle concentration and particle size. The results show that the sewage flow rate, the sewage viscosity and the particle concentration have a great influence on the deposition of particle fouling, and when the velocity increases from 0.5 m/s to 1.5 m/s under the condition that other parameters remain unchanged, the deposition rate increases by 2.3 times, the time for denudation to reach stability is shortened to 1/6 of the original, and the fouling thermal resistance decreases by 56%. When the sewage viscosity increases from 0.001 0 Pa·s to 0.003 0 Pa·s, the time for denudation to reach stability increases by 1.27 times, and the fouling thermal resistance increases by 1.25 times. When the particle concentration increases from 400 mg/L to 800 mg/L, the time for denudation to reach stability increases by about 1 time, and the fouling thermal resistance increases by about 1 time. The particle size has little effect on the fouling deposition characteristics, when the particle size increases from 1 μm to 40 μm, the deposition rate increases by only 14%, and the fouling thermal resistance increases only 12.8%. This studys results can be used as a reference for the design, operation and descaling of sewage heat exchangers.
Keywords:U-shapedsewageheatexchangetube;particulatefouling;depositioncharacteristic;denudation;thermalresistance;numericalsimulation