LDV measurements have been taken in a disc chamber four-stroke reciprocating engine under motoring conditions. Two non-simultaneous velocity components have been recorded at three different locations on the mid-plane of the TDC clearance during the intake and compression strokes for three different speeds (600, 800, 1000 rpm). The locations are characterized by different flow conditions (near the intake valves; on the cylinder axis; near the exhaust valves). The combination of different engine speeds and different chamber locations enables one to look both at the global behavior of the flow and at the details of the turbulence time-evolution. The aim of the research is to identify the frequency which can be considered a separation between “true” turbulence and cycle-by-cycle variation of the mean flow and to analyze the variation of such a frequency with the measuring location and with the engine speed. The analysis has been carried out by using different tools: the non-stationary velocity autocorrelation function, the power spectrum and the cycle-resolved analysis based on the frequency filter. The various approaches offer complementary perspectives of the same phenomenon, which give a clear perception of the physical meaning of the most frequently used investigation tools. The results show that the cut-off frequency increases as the engine speed increases and as the measuring point moves away from the ordered jet coming out of the intake valves. [S0742-4795(00)01204-7]

Issue Section:
In-Cylinder Processes
Keywords:
internal combustion engines, turbulence, laser Doppler anemometry, flow measurement, velocity measurement
Topics:
Compression, Cycles, Engines, Flow (Dynamics), Separation (Technology), Turbulence, Valves, Exhaust systems
1.
Witze, P. O., 1980, “A Critical Comparison of Hot-Wire Anemometry and Laser Doppler Velocimetry for I.C. Engine Applications,” SAE Paper 800132.
2.
Reuss, D. L., Adrian, R. J., Landreth, C. C., French, D., and Fansler, T. D., 1989, “Instantaneous Planar Measurements of Velocity and Large-Scale Vorticity Stain Rate in an Engine Using Particle-Image Velocimetry,” SAE Paper 890616.
3.
Witze, P. O., 1976, “Hot-Wire Measurements of the Turbulence Structure in a Motored Spark-Ignition Engine,” AIAA 14th Aerospace Sciences Meeting, Washington, D.C.
4.
Lancaster, D. R., 1976, “Effects of Engine Variables on Turbulence in a Spark-Ignition Engine,” SAE Paper 760159.
5.
Lancaster, D. R., Krieger, R. B., Sorenson, S. C., and Hull, W. L., 1976, “Effects of Turbulence on Spark-Ignition Engine Combustion,” SAE Paper 760160.
6.
Rask R. B., 1984, “Laser Doppler Anemometer Measurements of Mean Velocity and Turbulence in Internal Combustion Engines,” ICALEO ’84 Conference Proceedings, Laser Institute of America, Boston.
7.
Rask
,
R. B.
,
1985
, “
Comparison of Window, Smoothed-Ensemble, and Cycle-by-Cycle Data Reduction Techniques for Laser Doppler Anemometer Measurements in a Motored IC Engine
,”
ASME J. Fluids Eng.
,
107
, pp.
232
–
240
.
8.
Liou
,
T. M.
, and
Santavicca
,
D. A.
,
1985
, “
Cycle Resolved LDV Measurements in a Motored IC Engine
,”
ASME J. Fluids Eng.
,
107
, pp.
232
–
240
.
9.
Fansler, T. D., and French, D. T., 1988, “Cycle-Resolved Laser-Velocimetry Measurements in a Reentrant-Bowl-in-Piston Engine,” SAE Paper 880377.
10.
Catania
,
A. E.
, and
Mittica
,
A.
,
1989
, “
Extraction Techniques and Analysis of Turbulence Quantities From In-Cylinder Velocity Data
,”
ASME J. Eng. Gas Turbines Power
,
111
, pp.
466
–
478
.
11.
Fraser, R. A., and Bracco, F. V., 1989, “Cycle-Resolved LDV Integral Length Scale Measurements Investigating Clearance Height Scaling, Isotropy, and Homogeneity in an I.C. Engine,” SAE Paper 890615.
12.
Fansler, T. D., 1993, “Turbulence Production and Relaxation in Bowl-in-Piston Engines,” SAE Paper 930479.
13.
Catania, A. E., Dongiovanni, C., Mittica, A., Molina, G., and Spessa, E., 1995, “A New Test Bench for HWA Fluid-Dynamic Characterization of a Two-Valved In-Piston-Bowl Production Engine,” SAE Paper 952467.
14.
Amelio, M., Belli, M., Bova, S., and Florio, G., 1994, “LDA Flow Field Characterization in a Motored Reciprocating Engine,” in PD-Vol. 64-8.3, Engineering Systems Design and Analysis (ESDA) Conference, ASME PD, 8, Part C, pp. 597–604.
15.
Lorenz, M., and Presher, K., 1990, “Cycle Resolved LDV Measurements on a Fired SI-Engine at High Data Rates Using a Conventional Modular LDV-System,” SAE Paper 900054.
16.
Bracco, F. V., 1985, “Modeling and Diagnostics of Combustion in Spark-Ignition Engines,” Proc. of International Symposium on Diagnostics and Modeling of Combustion in Reciprocating Engines, (COMODIA 85), Tokyo, pp. 1–13.
17.
Bendat, J. S., and Piersol, A. G., 1986, Random Data Analysis and Measurement Procedures, 2nd ed., Wiley, New York.
18.
Heywood, J. B., 1988, Internal Combustion Engine Fundamentals, McGraw-Hill, New York.
19.
Rask, R. B., 1981, “Comparison of Window, Smoothed-Ensemble, and Cycle-by-Cycle Data Reduction Techniques for Laser Doppler Anemometer Measurements of In-Cylinder Velocity,” in Morel, T., Lohman, R. P., and Racklay, J. M., eds., Fluid Mechanics of Combustion Systems, pp. 11–20, ASME, New York.
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