Wind tunnel test manner null of automobile exhaust gas diffusing the semi- underground

摘要

PURPOSE: To eliminate the difference between an experiment and analysis and to evaluate the concentration of exhaust gas by obtaining the air exchange rate with outer air at the upper surface of the opening part of a canal road and the air exchange rate between the facing lanes at the central part in the width direction of the road by specified expressions. ;CONSTITUTION: The amount of gas, which flows out of the opening part of a canal road model into a wind-tunnel wind path, is made to be T. The amount of the gas, which is exhausted from the point source of the canal road, is made to be Q. The amount of the gas, which flows into the running direction of the point-source-side lane, of the canal road, is made to be S. The amount of the gas, which flows into the running direction of the opposite lane, is made to be R. The distribution of the concentration of the gas in the running direction in the roadway on the point source side at the opening part is made to be CA (x). The distribution of the concentration of the gas in the running direction in the roadway of the opposite lane is made to be CB (x). The widths of the point-source-side lane and the opposite lane are both made to be W. The depth of the canal is made to be H. At this time, the air exchange rate (q) with outer air per unit area at the upper surface of the opening part of the canal road and the air exchange rate q₀ per unit area between the facing lanes at the central part of the width direction of the road are obtained by the expressions. The air exchange rate is obtained based on the amount of the gas, which is leaked out of the roadway. Thus, the difference of leakages between the experiment and the analysis is eliminated, and the wind-tunnel testing method for the exhaust gas diffusion for correctly evaluating the concentration is obtained.;COPYRIGHT: (C)1993,JPO&Japio