VARIATION OF VELOCITY AND PRESSURE

As the air flows through the impeller and diffuser, there is a variation of both velocity and pressure as shown in Fig. 14.2. Nearly half of the total pressure rise takes place in the impeller and the remaining half occurs in the diffuser. A pressure ratio of 4 can be achieved in single-stage compressors. For higher pressure ratios, multi-stage compressors are used. A pressure ratio of 12:1 is possible with multi-stage compressors.

Figure 14.2 Variation of velocity and pressure of air passing through impeller and diffuser