CAJ | 학술논문

应用计算流体动力学理论,针对一款双气门单缸四冲程汽油机,对其在3500r·min~(-1)和5500r·min~(-1)两种工况下的进气、压缩及燃烧过程进行了数值仿真研究.研究结果表明:高转速时的滚流存在曲轴角度比低转速时长,但到达压缩后期滚流都已破碎,挤流成为湍流的主要表现形式;从进气中期到压缩冲程结束,低转速工况缸内湍流平均时间尺度大于高转速工况,在进气末期至压缩初期尤为突出;压缩中期缸内平均时间尺度变化较为剧烈;压缩上止点前20℃A左右缸内平均时间尺度达到谷值;点火时刻两种工况缸内长度尺度最大值均不超过0.46mm, 小于火花塞击穿放电后瞬间的火核尺寸,且最大尺度均存在于气缸进气门侧.
응용계산류체동역학이론,침대일관쌍기문단항사충정기유궤,대기재3500r·min~(-1)화5500r·min~(-1)량충공황하적진기、압축급연소과정진행료수치방진연구.연구결과표명:고전속시적곤류존재곡축각도비저전속시장,단도체압축후기곤류도이파쇄,제류성위단류적주요표현형식;종진기중기도압축충정결속,저전속공황항내단류평균시간척도대우고전속공황,재진기말기지압축초기우위돌출;압축중기항내평균시간척도변화교위극렬;압축상지점전20℃A좌우항내평균시간척도체도곡치;점화시각량충공황항내장도척도최대치균불초과0.46mm, 소우화화새격천방전후순간적화핵척촌,차최대척도균존재우기항진기문측.
The intake, compression and combustion strokes of a twovalve gasoline engine working individually at 3500 and 5500 rpm are diagnosed by using CFD method. The results show that tumble maintain longer with higher engine speed, but both of them have broken up before the late stage of compression, when squish control the flow field; from the middle stage of intake to the end of compression stroke, mean time scale magnitude with lower engine speed is higher, especially from late intake stroke to early compression stroke; during the middle compression stroke, time scale change sharply; 20℃A BTDC during the compression stroke, time scale reach the bottom; both the maximum of length scale at ignition time under the two work conditions are less than 0.46mm,which is less than flame kernel size during early development time, and they both exist near the intake valve side.