供液方式对蒸发平板温度场的影响

Influence of different mode of liquid supply on the temperature field of evaporated plate

研究相同工况下平板速冻机不同供液方式的温度场分布,分析造成平板冻结速率不均的原因。分别进行冷凝温度为35℃时射流泵和膨胀阀供液的速冻试验。结果表明:冻结结束时,使用膨胀阀供液冻品最低温度达到-35.9℃,冻品最大温差17.55℃,各层平板温差都较大,平板温度分布较为混乱;射流泵供液时,冻品的温度各层分布均匀,冻结结束时所有冻品最大温差5.54℃,同时各层冻品的温差由上至下逐渐减小,平板冻结速率逐渐增加,其中最底层平板冻结时间比最上层约短9.1%。证明蒸发平板的温度分布对系统冻结时间和能耗有影响。

This paper studied the temperature distribution of different mode of liquid supply in plate freezer under the same working condition,and analyzed the reasons for the inequality freezing rate of the flat plate.The freezing experiment of the fluid supply with ejector and the expansion valve at the same condense temperature in 35 ℃was carried out respectively.The results showed that：at the end of freezing,the minimum temperature reached to-35.9 ℃ by using expansion valve,and the maximum temperature difference of frozen products was 17.55 ℃.The temperature difference of each layer was large,and the temperature distribution of plate was chaotic.In mode of ejector supplying liquid,frozen temperature distribution was uniform,the maximum temperature difference was 5.54℃at the end of experiment.Meanwhile,each layer plate of temperature decreases gradually from top to bottom,freezing rate increases gradually,and the bottom plate freezing time was shorter than the top about 9.1%.To a certain extent,this study can prove the effect of the temperature difference distribution of the evaporated plate on the freezing time and energy consumption.