McKernan John L, Ellenbecker Michael J, Holcroft Christina A, Petersen Martin R
Division of Surveillance, Hazard Evaluation and Field Studies, National Institute for Occupational Safety and Health, 4676 Columbia Parkway, MS-R14, Cincinnati, OH 45226, USA.
Ann Occup Hyg. 2007 Nov;51(8):725-38. doi: 10.1093/annhyg/mem053. Epub 2007 Nov 2.
Our understanding of heat transfer and meteorological theories and their applications for engineering control design have been refined since the collective work in ventilation engineering for manufacturing process was published by Hemeon in 1955. These refined theories were reviewed and used to develop a newly proposed equation to estimate buoyant plume area (A). The area is a key parameter in estimating the plume volumetric flow (Q=UA) required for exothermic process control. Subsequent to developing a theoretical equation for plume area (A), plume velocity and area data were collected in the laboratory using a thermal anemometer and a scale-model exothermic process. Laboratory results were compared to solutions provided by the proposed, American Conference of Governmental Industrial Hygienists (ACGIH) and Hemeon plume area equations to determine which equation most closely matched the laboratory data. To make this determination, either t-tests or Wilcoxon signed-rank tests were conducted (based on examination of data normality) to determine the difference between collected data and solutions from the proposed, ACGIH and Hemeon equations. Median differences and P-values from Wilcoxon signed-rank tests (non-parametric) indicate that the ACGIH and Hemeon plume area equations provide significantly lower values than the laboratory data. However, the proposed equation provided solutions that were not significantly different from the collected data. Results indicate that the plume area equations currently recommended by the ACGIH and Hemeon are not as accurate as the proposed equation over the range of parameters investigated.
自1955年赫米恩发表了关于制造过程通风工程的集体研究成果以来，我们对传热和气象理论及其在工程控制设计中的应用的理解得到了完善。这些完善后的理论经过了审查，并被用于推导一个新提出的估算浮力羽流面积（A）的方程。该面积是估算放热过程控制所需羽流体积流量（Q = UA）的关键参数。在推导了羽流面积（A）的理论方程之后，使用热风速仪和缩尺模型放热过程在实验室中收集了羽流速度和面积数据。将实验室结果与新提出的、美国政府工业卫生学家会议（ACGIH）和赫米恩羽流面积方程提供的解进行比较，以确定哪个方程与实验室数据最匹配。为了做出这一判断，进行了t检验或威尔科克森符号秩检验（基于对数据正态性的检验），以确定收集到的数据与新提出的、ACGIH和赫米恩方程的解之间的差异。威尔科克森符号秩检验（非参数）的中位数差异和P值表明，ACGIH和赫米恩羽流面积方程提供的值明显低于实验室数据。然而，新提出的方程提供的解与收集到的数据没有显著差异。结果表明，在所研究的参数范围内，ACGIH和赫米恩目前推荐的羽流面积方程不如新提出的方程准确。
