摘 要:为了提高海参的干燥质量,利用高压电场和真空冷冻对海参进行了 2 种不同时段的联合干燥试验,即海参分别先进行 3 h 和 5 h 的高压电场干燥, 然后再进行真空冷冻干燥, 并与单纯高压电场及单纯真空冷冻干燥就干燥时间、电能消耗以及干燥后产品的质构、复水率、收缩率、蛋白质和酸性粘多糖含量等品质指标进行了比较。研究结果表明,较之单纯真空冷冻干燥,两种联合干燥用时更少,能耗更低,3 h 和 5 h 联合干燥分别节能 19.5%和 32.6%。与单纯高压电场干燥相比,联合干燥的海参质量得到了显著提高,所干燥的海参收缩率和硬度更小,复水率和蛋白质含量更高,感官品质更好。
The performance of a vertical axis wind turbine with and without a diffuser was studiedusing direct force measurement technique applied to a scaled model of the rotor in awater tunnel. The experiment was conducted at different tip-speed ratios. The maximumpower coefficient for the turbine was found to be equal to 0.35 for the rotor with diffuserand to 0.26 for the rotor without diffuser. Therefore, the maximum power coefficient wasincreased by 35% when the diffuser was used in the configuration.In the second part of this work, the flow patterns downstream of the turbine werestudied by the particle image velocimetry (PIV) technique. Six different tip-speed ratioswere considered for each configuration (with and without a diffuser). The vorticity andthe streamline plots provide insight into the flow physics in each configuration. Inaddition, the swept area of a full-scale rotor was calculated for both a diffuser-augmentedand a bare turbine for a range of power outputs.