Expansion turbines rotor

Radial-flow expansion turbines are normally single-stage, with combination impulse reaction blades and a rotor resembling a centrifugal... 

Porous aluminum titanate DMO has both a low thermal expansion coefficient (nearly zero at least up to 600°C) and a low thermal conductivity, suggesting possible applications in thermal barriers and abradable seals for turbine rotor shrouds [116] and automobile exhaust port liners and gas desulfurization nozzles [117]. Other possible thermal applications of silicon carbide reinforced DMO include heat exchangers [117] and flaps and seals in the afterburners of jet engines [119]. In addition, SiC particulate-reinforced DMO could serve as a lossy insert for high powered microwave tubes, withstanding temperatures up to 1000°C in ultrahigh vacuum. 

High Temperature. The low coefficient of thermal expansion and high thermal conductivity of sihcon carbide bestow it with excellent thermal shock resistance. Combined with its outstanding corrosion resistance, it is used in heat-transfer components such as recuperator tubes, and furnace components such as thermocouple protection tubes, cmcibles, and burner components. Sihcon carbide is being used for prototype automotive gas turbine engine components such as transition ducts, combustor baffles, and pilot combustor support (145). It is also being used in the fabrication of rotors, vanes, vortex, and combustor. 

The overall effieieney of a radial-inflow turbine is a funetion of effieieneies from various eomponents sueh as the nozzle and rotor. A typieal turbine expansion enthalpy/entropy diagram is shown in Figure 8-7. The total enthalpy remains eonstant through the nozzle, sinee neither work nor heat is transferred to or from the fluid. Within the rotor, the total enthalpy ehanges. Downstream of the rotor the total enthalpy remains eonstant. 

A turbine design where the expansion of steam occurs entirely in fixed nozzles. The steam jets from the nozzles are directed into disc-mounted buckets on the rotor forcing the shaft to rotate. 

As the observed power deficit had been explained to a very large extent, several measures were identified to enable its reduction. One measure would be to optimize the flow conditions for the inflow and outflow areas of the compressor and turbine sections in order to minimize the pressure drop losses and to achieve an optimum inflow into the blading. Moreover, a reduction of the blade gap losses would be required. That could be achieved by a reduction in rotor vibration and better selection of materials. The materials for both the rotor and the stationary blade carrier should be selected to optimize thermal expansions to achieve minimum gaps at operating conditions. One approach would be the replacement of the non-cooled austenitic stationary blade carrier in favor of a ferritic one, with cooling provided at necessary locations. Preferably no cooling at 750 C should be provided at all, taking into account possible improvements in avaible blade and rotor materials. A third approach that seems to be possible would be a further optimization of the stationary blade profiles and rotor blade profiles. 

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