柴油机缸内涡流研究

Research on In- cylinder Swirl of Diesel Engine

在稳流模拟试验台和CA1105柴油机改装的倒托柴油机试验台上，对不同气门升程下模拟汽缸内气流的流量、流量系数、角动量流率和涡流结构进行了研究。试验结果表明，随着气门升程的增大，流量、流量系数和角动量流率也随之增大，但流量和流量系数的增长率逐渐减小，角动量流率的增长率逐渐增大；角动量流率沿汽缸轴线方向不断衰减，涡流角动量流率越大，衰减率也越大。涡流转速越高，衰减越快，计算涡流比时应该考虑涡流在缸内的衰减和进气压差的变化影响；在压缩行程和膨胀行程，涡流逐渐趋于刚体涡流。

Based on the different valve lift, flow, flow coefficient, angular momentum flux and in - cylinder swirl were studied under the steady state flow rig and the motored CA1105 diesel engine. The experimental results show that with valve lift rises, flow, flow coefficient, angular momentum flux increase respectively, flow and flow coefficient＇ s growth rate decrease gadually, and angular momentum flux presents attenuation along cylinder axes, the higher the swirl speed, the more rapidly its decay. When swirl ratio is calculated, the swirl speed＇ s decay and aspiration pressure＇ s change should be considered. The swirl goes toward rigid during the compression and expansion stroke.