摘要：Resource-scarce regions with serious COVID-19 outbreaks do not have enough ventilators to support critically ill patients,and these shortages are especially devastating in developing *** help alleviate this strain,we have designed and tested the accessible low-barrier in vivo-validated economical ventilator(ALIVE Vent),a COVID-19-inspired,cost-effective,open-source,in vivo-validated solution made from commercially available *** ALIVE Vent operates using compressed oxygen and air to drive inspiration,while two solenoid valves ensure one-way flow and precise cycle *** device was functionally tested and profiled using a variable resistance and compliance artificial lung and validated in anesthetized large *** functional test results revealed its effective operation under a wide variety of ventilation conditions defined by the American Association of Respiratory Care guidelines for ventilator *** large animal test showed that our ventilator performed similarly if not better than a standard ventilator in maintaining optimal ventilation *** FiO2,respiratory rate,inspiratory to expiratory time ratio,positive-end expiratory pressure,and peak inspiratory pressure were successfully maintained within normal,clinically validated ranges,and the animals were recovered without any *** regions with limited access to ventilators,the ALIVE Vent can help alleviate shortages,and we have ensured that all used materials are publicly *** this pandemic has elucidated enormous global inequalities in healthcare,innovative,cost-effective solutions aimed at reducing socio-economic barriers,such as the ALIVE Vent,can help enable access to prompt healthcare and life saving technology on a global scale and beyond COVID-19.

摘要：针对45°叶型转折角扩压叶栅及增加小叶片后组成的大小叶片叶栅,分别测量了其在设计工况及不同气流攻角下的叶栅气动性能,通过PIV实验获得了对应工况下的叶栅内部流动状态.结果表明:增加小叶片后,叶片压力面至吸力面的压力梯度明显降低,大叶片载荷降低;在设计工况下,叶栅气流落后角仍可参考霍威尔半经验公式进行计算,但偏离设计工况后,该公式存在较大误差;大小叶片叶栅的气流落后角仅在小气流攻角下明显减小,在其余工况下变化不大;不同气流攻角下小叶片对大叶片表面气流流动分离起到约束作用;在设计工况至大气流攻角工况变化过程中,叶栅扩压损失有所降低.