低温氮气中液滴喷雾冻结过程的研究

Study on the Spray Freezing Process of Droplets in Low Temperature Nitrogen

喷雾冷冻干燥技术中液滴的冻结过程对干燥产品的品质具有较大影响。使用集总热容法建立了喷雾冻结过程数学模型,采用CFD(Computation Fluid Dynamic)数值模拟的方法对建立的数学模型进行验证对比。数学模型求解结果与模拟结果吻合度较好,最终冻结温度最大相差10 K,误差率4%,冻结速率最大相差20 K/s,误差率为7.1%。喷雾冻结实验结果与数学模型求解结果最大相差为8 K,相对实验结果误差率最大为5.2%。

The freezing process of droplets in spray freeze drying technology has a great influence on the quality of dried products.A mathematical model of the spray freezing process was established using the lumped heat capacity method,and the established mathematical model was verified and compared by means of CFD(Computation Fluid Dynamic)numerical simulation.The results of the mathematical model are in good agreement with the simulation results.The final freezing temperature differs by a maximum of 10 K,with an error rate of 4%,and the freezing rate differs by a maximum of 20 K/s,with an error rate of 7.1%.The maximum difference between the spray freezing experimental results and the mathematical model solution results is 8K,and the maximum error rate relative to the experimental results is 5.2%.