三种不同类型的厨房排气系统，即壁挂式高架、岛式和下吸式，都受到了密切的研究。风机按照ASHRAE标准51-1985中给出的程序进行能耗和气流额定值测试。排气管中的速度分布通过皮托管横向测量。测得的速度剖面与充分发展的湍流剖面之间存在微小差异。通过使用管道中等于中心线速度87%的平均速度来获得气流速率。绘制了不同排气系统的特征风扇曲线。利用无污染流动可视化系统，对炉灶顶面与罩底之间的流场进行了定性研究。 研究了添加侧挡板、周边槽和遮阳板或改变机罩间隙高度的效果，以显示使用流动可视化技术提高通风系统的捕获效率。增加侧挡板大大提高了头顶罩的捕获效率；然而，在应用周长槽后，几乎没有注意到效果。通过减小间隙高度，捕获效率得到提高。排气位于炉灶两侧或中间平面的下吸式系统仅对低矮的烹饪锅有效。通过增加罐的高度，它们的捕获效率显著降低。捕集效率和气流速率之间的关系很重要，因为它直接关系到所需的室外补充空气量以及加热或冷却所需的能量。 使用安装在手动横移装置上的全向热线探针定量测量气流速度。研究发现，随着距排气口距离的增加，空气流速值迅速减小。一个简单的势流模型被用来计算相应的空气速度。理论速度等值线与实测值吻合良好。这三个通风系统通过测量放屁产生的输出噪声与环境声级之间的关系来对声音进行评级。在C称重秤上，报告的声音增加了0到24 db。引文:研讨会，ASHRAE交易，第95卷，pt。1989年，芝加哥

Three different types of kitchen exhaust systems, namely, wall-mounted overhead, island, and downdraft, are closely investigated. Fans are tested for energy consumption and airflow ratings following the procedure given in ASHRAE Standard 51-1985. The velocity profile in the exhaust duct is measured using a pitot tube traverse. There is a slight difference between the measured velocity profile and the profile for fully developed turbulent flow. The airflow rate is obtained by using an average velocity in the duct equal to 87% of the centerline velocity. Characteristic fan curves are plotted for the different exhaust systems. The flow field between the top surface of the range and the bottom of the hood is quafitatively studied by means of a noncontaminating flow visualization system. The effects of adding side baffles, a perimeter slot, and a visor or varying the hood clearance height are studied to show the enhancement of the capturefficiency of the ventilation system using the flow visualization technique. Adding side baffles greatly increases the capture efficiency for overhead hoods; however, little effect is noticed after applying the perimeter slot. The capture efficiency improves by decreasing the clearance height. Downdraft systems, with the exhaust located either at the sides or mid-plane of the range, are effective only for low cooking pots. Their capturefficiency is dramatically reduced by increasing the pot height. The relationship between capture efficiency and airflow rate is important, since it relates directly to the amount of outdoor makeup air required and the energy required to heat or cool it. The airflow velocities are measured quantitatively using an omnidirectional hot wire probe mounted on a manual traversing device. The air velocity magnitude is found to decrease rapidly with increasing distance from the exhaust opening. A simple potential flow model is used to calculate the corresponding air velocities. The theoretical velocity contours agree closely with the measured values. The three ventilation systems are rated for sound by measuring the output noise generated by the farts relative to the ambient sound leveL An increase of 0 to 24 db is reported on a C weighing scale.