The article deals with axial-symmetric subsonic air-to air ejector with a diffuser adapted for boundary layer suction. The diffuser, which is placed after the mixing chamber of the ejector, has a high divergence angle and is therefore inefficient. To increase efficiency, the diffuser is equipped with a slot enabling boundary layer suction. The effect of boundary layer suction on the airflow in the ejector was measured, as were the static pressure distribution on the mixing chamber wall and ejector characteristics. Both diffuser and ejector efficiency were calculated. Although the efficiency of the diffuser was increased, the efficiency of the ejector itself remained low. and Obsahuje seznam literatury
One of vital and challenging tasks is to improve double suction pump performance in conditions when essential changes of their parameters are required without playing with their dimension in case of adapting their capacity to seasonality or flow-rtae change for a long time interval or for pipelines at various stage of their development. In this paper a few design options of flow parts executed for the same casing have been examined:
- Nominal mode: Semi-volute suction chamber, double suction impeller and double volute discharge chamber;
- Suboptimal mode: replaceable impellers and diffusers are used (same suction and discharge chambers)
Numerical analysis results of the flow parts are presented in this article. Double suction pumps with projected diffuser for replaceable rotor with 0.6 Qn flow-rate and with perspective diffusers engineered within ANSYS CFX-12.0. The latter (perspective diffusers) have been analyzed to find final ways to reduce hydraulic losses. Q-H, power consumption and performance curves are also given. Numerical experiment is an effective method for predicting patterns of characteristic curves even for such sophisticated flow parts as double suction pumps with a combined discharge chamber. and Obsahuje seznam literatury