Advanced SearchSearch Tips
Discharge Characteristics of Rotating Orifices with Length-to-Diameter Ratios and Inlet Corner Radii
facebook(new window)  Pirnt(new window) E-mail(new window) Excel Download
 Title & Authors
Discharge Characteristics of Rotating Orifices with Length-to-Diameter Ratios and Inlet Corner Radii
Ha, Kyoung-Pyo; Kang, Se-Won; Kauh, Sang-Ken;
  PDF(new window)
The effect of rotation on the discharge coefficient of orifices with various length-to-diameter ratios and two different inlet corner radii was studied. Length-to-diameter ratios of the orifices range from 0.2 to 10, while the inlet shapes are square edged, or round edges of radius-to-diameter ratio of 0.5. From the experiment, we found that rotational discharge coefficient and Rotation number, when based on ideal exit velocity of the orifice considering momentum transfer from the rotor, describe the effect of rotation very well. In this study, the discharge coefficients of rotating orifices are shown to behave similar to those of the well-known non-rotating orifices. For both rotating and non-rotating orifices, the discharge coefficients increase with the length-to-diameter ratio until a maximum is reached. The flow reattachments in the relatively short orifices are responsible for the increase. The coefficient then decreases with the length-to-diameter ratio due to the friction loss along the orifice bore. The length-to-diameter ratio that yields maximum discharge coefficient, however, increases with the Rotation number because the increased flow-approaching angle requires larger length-to-diameter ratio for complete reattachment. The length-to-diameter ratio for complete reattachment is shorter for round edged orifices than that of square edged orifices by about a unit length-to-diameter ratio.
Discharge Coefficient;Rotating Orifice;Rotation Number;Length-to-diameter Ratio;Corner Radius;
 Cited by
송출공의 회전이 송출계수와 압력계수에 미치는 영향,하경표;구남희;고상근;

대한기계학회논문집B, 2003. vol.27. 7, pp.948-955 crossref(new window)
Lichtarowicz, A., Duggins, R. K., and Markland, E., 1965, 'Discharge Coefficients for Incompressible Non-Cavitating Flow Through Long Orifices,' Journal of Mechanical Engineering Science, Vol. 7, No.2, pp. 210-219

McGreehan, W. F., and Schotsch, M. J., 1988, 'Flow Characteristics of Long Orifices with Rotation and Corner Radiusing,' Journal of Turbomachinery, Vol. 110, pp. 213-217

Hay, N., and Lampard, D., 1998, 'Discharge Coefficient of Turbine Cooling Holes: A Review,' Journal of Turbomachinery, Vol. 120, pp. 314-319

Hay, N., Khaldi, A., and Lampard, D., 1987, 'Effect of Crossflows on the Discharge Coefficients of Film Cooling Holes with Rounded Entries or Exits,' 2nd ASME/JSME Thermal Engineering Conference, Hawaii, pp.369-374

Hay, N., Lampard, D., and Benmansour, S., 1983, 'Effect of Crossflows on the Discharge Coefficient of Film Cooling Holes,' Journal of Engineering for Power, Vol. 105, pp. 243-248

Meyfarth, P. F., and Shine, A. J., 1965, 'Experimental Study of Flow Through Moving Orifices,' Journal of Basic Engineering, Dec., pp. 1082-1083

Wiles, W. F., 1976, 'Flow Through Holes in Rotating Discs,' Thermofluids Conference, Hobart, pp. 21-24

Wittig, S., Kim, S., Jakoby, R., and WeiBert, I., 1996, 'Experimental and Numerical Study of Orifice Discharge Coefficients in High-Speed Rotating Disks,' Journal of Turbomachinery, Vol. 118, pp. 400-407

Jakoby, R., Geis, T., Kim, S., and Wittig, S., 1997, 'Discharge Coefficients of Rotating Orifices with Radiused Inlet Corners,' Thirteenth International Symposium on Airbreathing Engines (ISABE XIII), Tennessee, USA.

Ha, K.-P., 1999, A Comprehensive Thermal Analysis on an Induction Motor with Axial Cooling Passages, Ph. D. Thesis, Seoul National University (in Korean)