Tip Losses in Reaction-Type Turbine Cascades in a Wide Range of Attack Angles

摘要

Experimental studies were performed of the tip energy losses in three reaction-type turbine shrouded cascades. The blade profiles differed mainly by the leading edge thickness while the trailing edges were practically the same. The flow exit angles for the three tested cascades were 24 degrees, 17 degrees, and 23.5 degrees, respectively. The pitch-chord ratio was practically optimal, and the blade assembly was 120 mm high. The inlet flow angle was varied from 20 to 154 degrees. The effective height of the blades was 105 mm. At high positive angles of attack, the end losses substantially increase. At negative angles of attack, the losses are considered to be approximately equal to those found at rated regimes. The leading edge of the profile practically does not affect the tip losses. (Author)