Fluid machinery is a machine which converts energy by using fluid as working medium, usually including hydro turbine, steam turbine, gas turbine, expander, wind turbines, pumps, fan, compressor, hydraulic coupler, hydraulic torque converter, and pneumatic tools, gas dynamic motor and hydraulic motor etc.
The energy used by fluid machinery is mostly the chemical energy of fuels (coal, oil and natural gas); which releases in the form of heat energy, and then transforms into mechanical energy or electric energy (such as steam turbine and gas turbine). In addition, the wind turbine, turbine and expander can be converted directly or converted to electric energy from the motivation. The hydraulic turbine, steam turbine and gas turbine are water, steam and gas. Pumps are transported by water, oil or other liquids. Fan and compressor transport all kinds of gas. The working medium of the wind turbine and the expander is air and other gases. The working medium of pneumatic tools and pneumatic motor is compressed air or other compressed gases. The working medium of hydraulic motor is hydraulic oil.
Due to the different role principle, structure forms and uses, the temperature, flow and pressure of working medium of various types of fluid machinery also have big difference. According to the working principle, the fluid machinery can be divided into volume type and dynamic type. Volume type fluid machinery relies on moving components to change the work volume to achieve energy conversion. Dynamic fluid machinery relies on the interaction of high speed rotating blades and fluid force to transfer energy, also known as turbine machinery. A jet also belongs to the dynamic type, and the working principle is that the high speed jet fluid is mixed with the suction fluid to exchange energy and transfer the energy. In addition, according to the structure, fluid machinery can be divided into rotary and reciprocating. Dynamic fluid machinery is usually rotary type, volume type fluid machinery both have a rotating type and reciprocating type.