{"id":5096,"date":"2024-12-18T11:49:48","date_gmt":"2024-12-18T03:49:48","guid":{"rendered":"https:\/\/turbineblade.net\/?p=5096"},"modified":"2024-12-18T11:49:49","modified_gmt":"2024-12-18T03:49:49","slug":"turbine-basics-turbine-and-blade-cooling-technology","status":"publish","type":"post","link":"https:\/\/turbineblade.net\/fr\/turbine-basics-turbine-and-blade-cooling-technology\/","title":{"rendered":"Turbine Basics – Turbine and Blade Cooling Technology"},"content":{"rendered":"

Axial flow turbine structure<\/strong><\/h2>

A turbine<\/a> is a rotary power machine that converts the enthalpy of a working fluid into mechanical energy. It is one of the main components of aircraft engines, gas turbines, and steam turbines. The energy conversion between turbines and compressors and airflow is opposite in procedure. The compressor consumes mechanical energy when it is running, and the airflow gains mechanical energy when it flows through the compressor, and the pressure and enthalpy increase. When the turbine is running, shaft work is output from the turbine shaft. Part of the shaft work is used to overcome the friction on the bearings and drive the accessories, and the rest is absorbed by the compressor.<\/p>

Only axial flow turbines are discussed here. The turbine in a gas turbine engine is usually composed of multiple stages, but the stator <\/a>(nozzle ring<\/a> or guide<\/a>) is located in front of the rotating impeller. The blade channel of the turbine element stage is convergent, and the high-temperature and high-pressure gas from the combustion chamber expands and accelerates in it, while the turbine outputs mechanical work.<\/p>

\"Axial<\/figure>

Heat transfer characteristics of turbine blade outer surface<\/strong><\/h2>

The convective heat transfer coefficient between the gas and the blade<\/a> surface is calculated using the Newton cooling formula.<\/p>

For the pressure surface and the suction surface, the convective heat transfer coefficient is the highest at the leading edge of the blade. As the laminar boundary layer gradually thickens, the convective heat transfer coefficient gradually decreases; at the transition point, the convective heat transfer coefficient suddenly increases; after the transition to the turbulent boundary layer, as the viscous bottom layer gradually thickens, the convective heat transfer coefficient gradually decreases. For the suction surface, the flow separation that may occur in the rear section will cause the convective heat transfer coefficient to increase slightly.<\/p>

\"Heat