درباره ما
NACA-TN-3696
A study of the high-speed performance characteristics of 90 degrees bends in circular ducts
Year: 1956
Abstract: The performance of four 90° bends in ducts of constant diameter with ratios of radius of curvature to diameter of 0.75, 1.00, 2.50, and 4.00 was investigated over a range of inlet Mach numbers extending up to the choking condition for both a thin and a thick inlet boundary layer. The variation of the measured longitudinal static-pressure gradients at low speed from those predicted by two-dimensional, incompressible, potential flow theory was determined. It was found that an increase in the inlet boundary-layer thickness decreased the choking Mach number by a very small amount for each of the elbows and had little effect on the other performance parameters. It was concluded that, for the type of elbows tested, a mean radius-diameter ratio of approximately 2.50 would yield the greatest inlet choking Mach number with the least loss of static and total pressure.
Show full item record
| contributor author | NASA - National Aeronautics and Space Administration (NASA) | |
| date accessioned | 2017-09-04T18:30:58Z | |
| date available | 2017-09-04T18:30:58Z | |
| date copyright | 01/01/1956 | |
| date issued | 1956 | |
| identifier other | IXONEEAAAAAAAAAA.pdf | |
| identifier uri | http://yse.yabesh.ir/std;query=author:%22NAVY%20-%206159DD6E273C9FCD0Facil/handle/yse/213180 | |
| description abstract | The performance of four 90° bends in ducts of constant diameter with ratios of radius of curvature to diameter of 0.75, 1.00, 2.50, and 4.00 was investigated over a range of inlet Mach numbers extending up to the choking condition for both a thin and a thick inlet boundary layer. The variation of the measured longitudinal static-pressure gradients at low speed from those predicted by two-dimensional, incompressible, potential flow theory was determined. It was found that an increase in the inlet boundary-layer thickness decreased the choking Mach number by a very small amount for each of the elbows and had little effect on the other performance parameters. It was concluded that, for the type of elbows tested, a mean radius-diameter ratio of approximately 2.50 would yield the greatest inlet choking Mach number with the least loss of static and total pressure. | |
| language | English | |
| title | NACA-TN-3696 | num |
| title | A study of the high-speed performance characteristics of 90 degrees bends in circular ducts | en |
| type | standard | |
| page | 29 | |
| status | Active | |
| tree | NASA - National Aeronautics and Space Administration (NASA):;1956 | |
| contenttype | fulltext |