Study on Evaluation Method of Flow Characteristics in Steady Flow Bench(3) - Velocity Profile(1)

Title & Authors
Study on Evaluation Method of Flow Characteristics in Steady Flow Bench(3) - Velocity Profile(1)
Park, Chanjun; Sung, Jaeyong; Ohm, Inyong;

Abstract
This paper is the third investigation on the evaluation methods of flow characteristics in a steady flow bench. In the previous works, several assumptions used in the steady flow bench were examined and the flow characteristics were estimated both by the conventional impulse swirl meter and a particle image velocimetry at 1.75B position. From these works, it was concluded that the assumption of the solid rotation might cause serious problems and both of the eccentricity and the velocity profile distort the flow characteristics when using the ISM at 1.75B plane. Therefore, the understanding of the detail velocity profiles is very important to keep discussing the issues about the steady flow evaluation method. For this purpose, the planar velocity profiles were measure at 1.75B position by particle image velocimetry and the characteristics were examined according to the valve angles and lifts. The results show that the planar velocity profiles of 11, 16, $\small{21^{\circ}}$ valve angle heads according to the lift are similar to each other, however, that of $\small{26^{\circ}}$ angle is an exceptional case in the all aspects. In addition, the swirl behaviors are not apparent up to 6~8 mm lift under the $\small{21^{\circ}}$ angle and somewhat arranged motions are observed over the whole plane near the highest lift. At this point, the narrower the angle, the lower the lift at which the swirl motions become clear. On the other hands, when the angle is $\small{26^{\circ}}$, the center of swirl is always farthest from the cylinder center and only the indistinct swirl is observed even if at the highest lift. Also, all the swirl centers are quite apart from the cylinder center so that the effect of eccentricity may not be negligible at 1.75B regardless the valve angle. Related to the tangential velocity along with the radial direction, the bands of the velocity distribution are very wide and the mean velocities of cylinder center basis are lower than the velocity which is assumed in the ISM evaluation. Lastly, the mean tangential velocity profiles of swirl center basis are sometimes higher than that of ISM-assumed up to 0.6 non-dimensional distance less than 6mm lift, however, as the lift increases the profiles are different according to the angles and profile $\small{11^{\circ}}$ is the most closed to the ideal profile. Consequently, the real velocity profile is far from the assumption of ISM evaluation.
Keywords
Steady flow bench;Swirl;Impulse swirl meter;PIV;Velocity profile;Intake valve angle;Eccentricity;
Language
Korean
Cited by
References
1.
I. Y. Ohm and C. J. Park, "Effect of Fuel Stratification on Initial Flame Development: Part 1-without Swirl," Int. J. Automotive Technology, Vol.7, No.5, pp.519-526, 2006.

2.
I. Y. Ohm and C. J. Park, "Effect of Fuel Stratification on Initial Flame Development: Part 2-low Swirl Condition," Int. J. Automotive Technology, Vol.9, No.6, pp.671-678, 2008.

3.
I. Y. Ohm and C. J. Park, "Effect of Fuel Stratification on Initial Flame Development: Part 3-high Swirl Condition," Int. J. Automotive Technology, Vol.12, No.5, pp.653-660, 2011.

4.
M. G. Kang and I. Y. Ohm, "Effect of Intake Flow Control Method on Part Load Performance in SI Engine - Comparison of Throttling and Masking," Transactions of KSAE, Vol.22, No.2, pp.156-165, 2014.

5.
M. G. Kang and I. Y. Ohm, "Effect of Intake Flow Control Method on Part Load Performance in SI Engine(2) - EGR Characteristics and Comparison of Dilution Method," Transactions of KSAE, Vol.22, No. 4, pp.121-130, 2014.

6.
J. B. Heywood, Internal Combustion Engine Fundamentals, McGraw-Hill, Int. Edn., Singapore, pp.343-345, 1988.

7.
R. Stone, Introduction to Internal Combustion Engines, 2nd Edn., McGraw-Hill, Hong Kong, pp.183-185, 1992.

8.
C. J. Park and I. Y. Ohm, "Study on Evaluation Method of Flow Characteristics in Steady Flow Bench(1) - Raising Issue," Transactions of KSAE, Vol.23, No.1, pp.88-96, 2015.

9.
C. J. Park and I. Y. Ohm, "Study on Evaluation Method of Flow Characteristics in Steady Flow Bench(2) - Comparison of ISM and PIV Measurement," Transactions of KSAE, Vol.23, No. 1, pp.139-147, 2015.

10.
I. Y. Ohm and C. J. Park, "In-cylinder Intake Flow Characteristics according to Inlet Valve Angle," Transactions of KSAE, Vol.14, No.3, pp.142-149, 2006.

11.
I. Y. Ohm and C. J. Park, "In-cylinder Compression Flow Characteristics According to Inlet Valve Angle," Transactions of KSAE, Vol. 14, No.4, pp.77-83, 2006.

12.
I. Y. Ohm and C. J. Park, "In-cylinder Intake Flow Characteristics of Helical Port Engines with Wide Valve Angle," Transactions of KSME-B, Vol.32, No.10, pp.761-768, 2008.

13.
I. Y. Ohm and C. J. Park, "In-cylinder Compression Flow Characteristics of Helical Port Engines with Wide Valve Angle," Transactions of KSME-B, Vol.33, No.1, pp.9-16, 2009.

14.
I. Y. Ohm and C. J. Park, "Effect of Inlet Valve Angle on In-cylinder Swirl Generation Characteristics(I)," Transactions of KSAE, Vol.16, No.6, pp.148-156, 2008.

15.
I. Y. Ohm and C. J. Park, "Effect of Inlet Valve Angle on In-cylinder Swirl Generation Characteristics(II)," Transactions of KSAE, Vol.17, No.1, pp.42-48, 2009.

16.
I. Y. Ohm, "Effects of Intake Valve Angle on Combustion Characteristic in an SI Engine," Int. J. Automotive Technology, Vol.14, No.4, pp.529-537, 2013.