Barber-Nichols Inc. (BNI) has extensive turbine design, analysis, fabrication, and testing expertise. BNI has a wide range of single and two-stage turbine experience which includes:
- Inlet temperatures from cryogenic to 1,370 °C (2,500 °F)
- Power levels from Watts to megawatts
- Rotational speeds exceeding 400,000 rpm
Applications have varied from commercial power generation applications to rocket engine turbopumps and torpedo drives. BNI produced hundreds of clean sheet turbine designs with most resulting in tested hardware. Please contact Barber-Nichols regarding your application or read on to learn more about the differences between Axial Flow Impulse, Axial Flow Reaction, and Radial Inflow Turbines.
Axial Flow Impulse Turbines
Axial Flow Impulse Turbines achieve the full pressure ratio across the nozzle and capture the kinetic energy via the turbine blades. Impulse turbines are ideally suited for applications where you need to keep the speed of the machine and the tangential velocity of the rotor low. In other words, they are often used in a lower specific speed range. For power generation systems, it is advantageous to operate at 3,600 rpm in order to drive a synchronous generator. In aerospace or other high-power density systems, the driving fluid is typically very energetic resulting in a high enthalpy drop across the turbine. For such applications, the impulse turbine can operate efficiently at a lower tangential velocity than reaction turbines. For lower flow applications, the impulse turbine can effectively operate with a partial admission nozzle outperforming a comparable reaction turbine.
Axial Flow Reaction Turbines
Axial Flow Reaction Turbines achieve part of the pressure ratio across the nozzle with the balance taken across the turbine blades. Reaction turbines are typically used for expanding hydrocarbon gases or fluorinated refrigerants where the high molecular weight results in a low enthalpy drop across the turbine, allowing a single stage. When air or steam is used, the head drop across a single turbine is usually too high, favoring multiple stages.
Radial Inflow Turbines
Radial Inflow Turbines also split the pressure ratio between the nozzle and the wheel. Inflow turbines can generate very high efficiencies when applied in the proper operating conditions, though typically requiring higher shaft speeds than axials. The most common application for the Radial Inflow Turbine is the exhaust driven turbocharger used on internal combustion engines. Millions of these units are used in automobiles, truck, aircraft, and industrial engines. Other applications include smaller gas turbines, organic Rankine cycle turbine generators, and air and natural gas separation plant turbo-expanders.