Abstract

This study used a laboratory-scale prototype of a hybrid heat pump vacuum dryer to investigate its effect on the drying rate of seafood products. Although seafood products such as oysters and sea cucumbers are the target products, the initial experiments were carried out using wet sponges with the same moisture content as the oysters. The experiments were carried out for ambient pressure, two decompression pressures and three temperature conditions to study the moisture removal capability and power consumption of the dryer prototype. The moisture extraction and specific moisture extraction rate are calculated for each experiment. An optimum operating condition was obtained from the experimental analysis at −0.2 bar and 55 °C. The experiment is again carried out with oysters at the optimum condition. The time consumed for drying 100 kg of oysters decreased considerably in the optimum drying condition without degradation of its color or texture. Additionally, a CFD analysis is carried out to study the internal flow behavior inside the drying chamber. Large recirculation regions and vortices were observed in the return flow duct formed between the drying chamber and tray enclosure. Guide vanes are installed to suppress the flow instabilities. The optimum operating condition along with the stable flow is recommended for industrial-scale design.

摘要

本研究使用实验室规模的混合热泵真空干燥机原型来研究其对海鲜产品干燥速率的影响。虽然牡蛎和海参等海鲜产品是目标产品，但最初的实验是使用与牡蛎相同水分含量的湿海绵进行的。在环境压力、两个减压压力和三个温度条件下进行了实验，以研究干燥机原型的除湿能力和功耗。计算每个实验的水分提取率和比水分提取率。从 -0.2 bar 和 55 °C 的实验分析中获得了最佳操作条件。再次用牡蛎在最佳条件下进行实验。在最佳干燥条件下，干燥 100 公斤牡蛎所花费的时间显着减少，而不会降低其颜色或质地。此外，还进行了 CFD 分析以研究干燥室内的内部流动行为。在干燥室和托盘外壳之间形成的回流管道中观察到大的再循环区域和涡流。安装导叶以抑制流动不稳定性。对于工业规模的设计，推荐最佳操作条件和稳定的流量。在干燥室和托盘外壳之间形成的回流管道中观察到大的再循环区域和涡流。安装导向叶片以抑制流动不稳定性。对于工业规模的设计，推荐最佳操作条件和稳定的流量。在干燥室和托盘外壳之间形成的回流管道中观察到大的再循环区域和涡流。安装导叶以抑制流动不稳定性。对于工业规模的设计，推荐最佳操作条件和稳定的流量。