Most evaporative cooling towers are arranged on building roof due to the limitation of space and noise,and acoustic barriers are always installed around cooling towers in practical applications.The existence of acoust...Most evaporative cooling towers are arranged on building roof due to the limitation of space and noise,and acoustic barriers are always installed around cooling towers in practical applications.The existence of acoustic barriers and crosswind may affect the recirculation phenomenon which is directly related to the operating performance of cooling towers.In this study,a physical and mathematical computation model is proposed to research the crosswind and distance between acoustic barriers and inlet of cooling towers.Both sensible and latent heat are considered in this research.The reflux flow rate and performance ratio are obtained to evaluate the recirculation and operating performance,respectively.The results show that the higher the crosswind velocity,the larger the reflux flow rate,and the lower the performance ratio of cooling tower groups.For high crosswind velocity,the presence of acoustic barriers is useful to inhibit reflux and improve operating performance,especially for ICE cooling tower groups.In addition,the optimum values are recommended for LiBrllCE cooling tower groups in the research cases The variation of reflux flow rate and performance ratio with the acoustic barriers' distance presents a parabolic tendency.展开更多
Saturated vapor pressure, critical evaporation temperature and evaporation loss rate of Fe-Ga alloy were calculated under different conditions of Ga and Fe contents with activity coefficients. The relationship between...Saturated vapor pressure, critical evaporation temperature and evaporation loss rate of Fe-Ga alloy were calculated under different conditions of Ga and Fe contents with activity coefficients. The relationship between the change of Ga content and melting time was determined. The results demonstrated that saturated vapor pressure of Ga was higher than that of Fe under the same conditions. The difference value of critical evaporation temperature of Ga with and without Ar was nearly 800 K. The critical evaporation temperature of Fe was higher than that of Ga under vacuum, indicating that Ga was more volatile than Fe. At 1800 K, the evaporation rate of Ga was 84 times higher than that of Fe in the melt of Fe81Ga19 alloy. Under this condition, the change of Ga content and smelting time kept a linear relationship. The higher the temperature was, the faster the Ga content decreased, which was consistent with theoretical calculations.展开更多
文摘Most evaporative cooling towers are arranged on building roof due to the limitation of space and noise,and acoustic barriers are always installed around cooling towers in practical applications.The existence of acoustic barriers and crosswind may affect the recirculation phenomenon which is directly related to the operating performance of cooling towers.In this study,a physical and mathematical computation model is proposed to research the crosswind and distance between acoustic barriers and inlet of cooling towers.Both sensible and latent heat are considered in this research.The reflux flow rate and performance ratio are obtained to evaluate the recirculation and operating performance,respectively.The results show that the higher the crosswind velocity,the larger the reflux flow rate,and the lower the performance ratio of cooling tower groups.For high crosswind velocity,the presence of acoustic barriers is useful to inhibit reflux and improve operating performance,especially for ICE cooling tower groups.In addition,the optimum values are recommended for LiBrllCE cooling tower groups in the research cases The variation of reflux flow rate and performance ratio with the acoustic barriers' distance presents a parabolic tendency.
基金Item Sponsored by National Natural Science Foundation of China(51161019)Project of Department of Science and Technology of Jiangxi Province of China(20133BBE50011)Project of Department of Science & Technology of Jiangxi Province of China(20141BDH80025)
文摘Saturated vapor pressure, critical evaporation temperature and evaporation loss rate of Fe-Ga alloy were calculated under different conditions of Ga and Fe contents with activity coefficients. The relationship between the change of Ga content and melting time was determined. The results demonstrated that saturated vapor pressure of Ga was higher than that of Fe under the same conditions. The difference value of critical evaporation temperature of Ga with and without Ar was nearly 800 K. The critical evaporation temperature of Fe was higher than that of Ga under vacuum, indicating that Ga was more volatile than Fe. At 1800 K, the evaporation rate of Ga was 84 times higher than that of Fe in the melt of Fe81Ga19 alloy. Under this condition, the change of Ga content and smelting time kept a linear relationship. The higher the temperature was, the faster the Ga content decreased, which was consistent with theoretical calculations.
