상호상관 PIV기법을 이용한 엔진 실린더내 난류의 공간적 해석
정구섭
†정용욱
*A SPACIAL ANALYSIS OF IN-CYLINDER TURBULENCE FLOW
IN SI ENGINE USING CROSS CORRELATION PIV
Kuseob Chung, Yongoug Chung
Key Words: PIV(입자영상유속계), Cross correlation(상호상관), SCV(스월제어밸브), Velocity
vector(속도벡터)
Abstract
Tumble or swirl flow is used adequately to promote mixing of air and fuel in the cylinder and to enlarge turbulent intensity in the late time of compression stroke. However, since in-cylinder flow is a kind of transient state with rapid flow variation, that is, non-steady state flow, swirl or tumble flow has not been analyzed sufficiently and not been recognized whether they are available for combustion theoretically yet. In the investigation of intake turbulent characteristics using PIV method, different flow characteristics were showed according to SCV figures. SCV installed engine had higher vorticity, turbulent strength by fluctuation and turbulent kinetic energy than a baseline engine, especially around the wall and lower part of the cylinder. Consequently, as swirl flow was added to existing tumble flow, it was found that fluctuation component increased and flow energy was conserved effectively through the experiment.
1. 서 론
2. 실험장치 및 방법
2.1 실험장치 및 실험조건 μ 2.2 속도벡터계산과 후처리 Blower Laminar flowmeter Manometer Cylinder head Tumble adaptor Laskin nozzle CCD camera Frame grabber Insight NT 1.22 Cylinderical lens Pressurized air Laser pulse synchronizer Laser power suppliesDual Nd:YAG laser Synchronizer
3. 실험결과 및 고찰
3.1 엔진 실린더내 유속분포 μ In Ex 0 60 40 20 In Ex 0 60 40 20 In Ex 0 80 60 40 20 0 20 -40 -20 40 In Ex 0 80 60 40 20 0 20 -40 -20 40 In Ex 0 80 60 40 20 0 20 -40 -20 40 In Ex 0 80 60 40 20 0 20 -40 -20 40 In Ex 0 80 60 40 20 0 20 -40 -20 40 In Ex 0 80 60 40 20 0 20 -40 -20 40 In Ex 0 60 40 20 In Ex 0 60 40 203.2 스월조절밸브 부착시 실린더내의 유동특성 3.3 실린더내의 와도(Vorticity)분포 ω ω = 1 2( ∂
v
∂x
-∂u
∂y
)3.4 실린더내의 난류강도 분포 0 2 4 6 8 10 0.5 1.0 1.5 2.0 Base SCVA SCVB SCVC urms (m /s ) Valve lift, L(mm) 0 2 4 6 8 10 0.5 1.0 1.5 2.0 Base SCVA SCVB SCVC vrm s (m /s) Valve lift, L(mm) 3.5 실린더내의 에너지소산 분포
4 3 2 6 6 3 1 1 2 1 1 1 1 1 1 7 3 8 3 5 5 1 1 14 1 7 15 3.33E-03 14 3.10E-03 13 2.88E-03 12 2.66E-03 11 2.44E-03 10 2.22E-03 9 2.00E-03 8 1.77E-03 7 1.55E-03 6 1.33E-03 5 1.11E-03 4 8.87E-04 3 6.65E-04 2 4.44E-04 1 2.22E-04 In Ex 0 80 60 40 20 0 20 -40 -20 40 9 9 14 13 11 12 3 4 7 7 6 7 2 2 3 2 3 8 5 4 7 4 4 9 3 15 1.64E-04 14 1.53E-04 13 1.42E-04 12 1.31E-04 11 1.20E-04 10 1.09E-04 9 9.83E-05 8 8.74E-05 7 7.65E-05 6 6.56E-05 5 5.47E-05 4 4.38E-05 3 3.29E-05 2 2.20E-05 1 1.11E-05 In Ex 0 80 60 40 20 0 20 -40 -20 40 15 1.41E-04 14 1.32E-04 13 1.22E-04 12 1.13E-04 11 1.03E-04 10 9.40E-05 9 8.46E-05 8 7.52E-05 7 6.59E-05 6 5.65E-05 5 4.71E-05 4 3.77E-05 3 2.83E-05 2 1.89E-05 1 9.51E-06 13 11 5 2 12 7 4 4 9 6 6 5 6 6 6 2 1 2 1 2 3 4 3 4 4 2 3 3 In Ex 0 80 60 40 20 0 20 -40 -20 40 11 3 1 5 5 1 6 5 6 4 5 6 6 3 3 4 4 3 2 1 2 2 4 3 3 2 3 3 1 5 15 1.51E-04 14 1.41E-04 13 1.31E-04 12 1.21E-04 11 1.11E-04 10 1.01E-04 9 9.06E-05 8 8.06E-05 7 7.05E-05 6 6.05E-05 5 5.04E-05 4 4.03E-05 3 3.03E-05 2 2.02E-05 1 1.01E-05 In Ex 0 80 60 40 20 0 20 -40 -20 40 0 2 4 6 8 1 0 0.0 2.0x10-5 4.0x10-5 6.0x10-5 8.0x10-5 1.0x10-4 B ase S C V A S C V B S C V C D issi p a ti on en er g y ( W /k g) V alve lift, L (m m )
