ENERGY TRANSFER FROM GAS FLOW TO TURBINE

Fig. 5-6 A typical turbine blade showing
twisted contour.

ENERGY TRANSFER FROM GAS FLOW TO TURBINE
6. From the description contained in para. 1, it will be seen that the turbine depends for its operation on the transfer of energy between the combustion gases and the turbine. This transfer is never 100 per cent because of thermodynamic and mechanicallosses, (para. 11). 

Fig. 5-7 Gas flow pattern through nozzle and blade

  7.when the gas is expanded by the combustion process (Part 4), it forces its way into the discharge nozzles of the turbine where, because of theirconvergent shape, it is accelerated to about the speed of sound which, at the gas temperature, isabout 2,500 feet per second. At the same time thgas flow is given a ’spin’ or ’whirl’ in the direction o rotation of the turbine blades by the nozzle guid vanes. On impact with the blades and during th subsequent reaction through the blades, energy is absorbed, causing the turbine to rotate at high speed and so provide the power for driving the turbine shaft and compressor.