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Indexed by:会议论文

Date of Publication:2018-01-01

Included Journals:SCIE、CPCI-S

Volume:1984

Abstract:Falling film evaporator applied in multi-effect evaporation system is operated under relatively small temperature difference. The thermal performance of the evaporator is sensitive to the temperature drop. In this paper, the thermal performance of the falling film evaporator was simulated based on a validated distributed parameter model. The temperature difference loss along the tube row direction and column directions were obtained in the evaporator of different geometrical dimensions. Considering the high sensitivity of the thermal performance to the thermodynamic loss, the maximum allowable temperature difference loss was defined as 20% of the apparent temperature difference of the evaporator. The concept of critical dimension of the tube bundle was proposed to prevent the local temperature difference loss from exceeding the maximum allowable temperature difference loss. The variation of the critical dimensions of the tube bundle was analyzed under different operating conditions. Results shown that the critical tube row number increased with the increment of the inlet seawater spray density but decreased with the increment of the inlet seawater salinity and the evaporation temperature. With the increment of the apparent temperature difference, the critical column number firstly exhibited an increasing trend, then reached a plateau; the critical tube column number decreased with the increment of the inlet seawater spray density and the apparent temperature difference but increased with the increment of the seawater salinity and the evaporation temperature.