In reaction turbines, the static pressure of the working medium in front of the rotor is higher than that behind it. In pure reaction turbines with a degree of reaction of one, the entire pressure energy in the rotor is converted to kinetic energy. This compressed-air driven experimental unit can be used to understand turbines powered by steam or water.
HM 272 is a single-stage, pure reaction turbine with a horizontal shaft. The rotor of the turbine has four outlet nozzles and is installed in a transparent housing. The air flows radially through the rotor and expands and accelerates as it exits through the outlet nozzles. The exiting air flow drives the turbine rotor according to the reaction principle. A band brake is used to apply a load to the turbine.
The inlet and outlet pressure at the turbine are indicated on manometers. The turbine torque is determined by measuring the force on the band brake. The speed is measured with an optical speed sensor. Torque, speed and temperatures are digitally displayed. The air flow rate is measured with a rotameter and set by means of a valve.
The turbine is fitted with a solenoid valve as a safety device in case of overspeed. The brake drum on the turbine shaft is cooled by means of the compressed air.