柴油机排气微粒部分流稀释取样系统的研制

设计了一种用于柴油机稳态工况下微粒测量的部分流稀释取样系统，该系统稀释通道内径为１５０ｍｍ全长为２３５０ｍｍ，稀释通道内稀释排气流量为５５６ｍ＾３／ｈ，雷诺数为７３０００，稀释比用ＣＯ２分析仪测量发动机排气和稀释通道内稀释排气的ＣＯ２浓度来计算，试验证明此仪器试验重复性良好。

Development of a Diesel Particulate Partial-Flow Dilution Sampling System

A partial flow dilution sampling system has been developed as a device for measuring the quantity of particulate matter emissions in the exhaust gas from automotive diesel engine in steady state operating conditions.The dimensions of the tunnel were 150 mm diameter and 2 350 mm length.A fraction of the total exhaust gas is drawn into the tunnel through particle transfer tube by low pressure in the mixing orifice and mixed with clean air in the tunnel.The volumetric flow rate in the tunnel as delivered by a vacuum fan was 556.65 m 3/h,corresponding to a Reynolds number of 73 000.The dilution ratio,defined as the ratio of the exhaust gas/air mixture flow in the tunnel to the exhaust gas flow into the tunnel was determined by CO 2 concentrations in the diluted exhaust and in the raw exhaust gas.A good repeatability of the system was testified.