Centrifugal air compressor: talk about the common sense of centrifugal air compressor
Centrifugal air compressor is a kind of turbine compressor, which has the characteristics of large gas volume, small volume, simple structure, smooth operation, convenient maintenance and free from pollution. Compus compressor next introduces the relevant common sense of centrifugal air compressor.
When the flow is reduced to a certain limit, the diffuser and impeller of the centrifugal air compressor will stall, and the downstream air begins to flow upstream. Under the flow limit, a full countercurrent occurs in the air on the exhaust side, and the compressed air in the downstream expands rapidly in the upstream, resulting in explosive sound. The countercurrent makes the pressure on the exhaust side drop sharply, then rise again and reverse current occurs again. This oscillation phenomenon is called turbine surge.
Because the cause of this phenomenon is the stall of diffuser or impeller, the method to prevent the stall should be considered. In the case that the kinetic energy exerted by the impeller of the centrifugal air compressor is constantly transformed into pressure, the stall reason is excessive deceleration. Once the reduction occurs, the general reducer of the diffuser will begin to stall first, and some designs may also have the impeller stall first.
Impeller is a kind of air accelerator, it is generally not considered that it will stall, but if the relative speed of the impeller and the air is considered, there may be deceleration in the impeller. In order to avoid stall as far as possible, the deceleration ratio of diffuser or impeller of centrifugal air compressor can be reduced, but this will increase the length along the radius direction, and the friction loss in the path will increase proportionally with the increase of this length. How to reduce the intake shell (volute) to effectively decelerate, is the key to improve the performance of centrifugal air compressor technology. The passage distance of vaneless diffuser without blade is also longer, and the loss will increase. However, on the other hand, its deceleration ratio is smaller than that of vaned diffuser, so it is not easy to stall.
Under the same conditions, that is, when running, do not change the number of revolutions and reduce the flow, improve the pressure ratio, the exhaust temperature of the dry screw compressor will rise, the screw will be burnt and damaged, so it has the exhaust temperature rise that triggers the shutdown device. Centrifugal air compressor also has a control device to avoid surge, but even if the control failure occurs surge, it generally will not cause damage, it will stop because of excessive vibration or countercurrent air temperature, that is, the intake temperature rises.
Shijiazhuang Compus Compressor Co., LTD., founded in 2004, is a high-tech enterprise specializing in the research and development, production and sales of air compressors. Its main products are oil-free mobile machines, drilling air compressors, centrifugal air compressors, screw air compressors and so on. Welcome to consult and cooperate!