Matching of Turbocharger

It involves matching of reciprocating engine to rotary compressor and turbine of Turbocharger.

• Impellor of compressor is chosen to provide desired airflow at engine power 80 - 90% MCR , thus taking into account.ie (a) Operating temperature and Engine room pressure (b) Pressure drop across air cooler.
• Once impellor output is fixed , diffuser is chosen which will provide compressor efficiency high , but ample surge margin.
• When compressor side design is final , turbine power requirements are known.
• The main variable on the  turbine side is nozzle size and this is matched to provide required compressor work and minimum restriction to exhaust gas flow.
• Smaller nozzle area: (a)Work output increase   (b) T\C speed increase (c) Air delivery pressure increase