An Israeli company, sponsored by the country's defence ministry, is developing a new type of jet engine based on an orbiting combustor nozzle (OCN).
The company, R-Jet Engineering , employs mainly new immigrants from Russia who worked in the Soviet Union's aerospace industry. State-owned Rafael Armament Development Authority owns 10% of the company's shares.
According to company president David Lior, the OCN concept allows the compressor- created vortex to flow continuously through an annular combustor into a coaxial turbine, instead of dissipating.
The combustor rotates with the compressor and turbine. The turbine design is similar to a convergent-divergent nozzle, he says, capable of transmitting high power at higher efficiencies.
According to Lior, the OCN eliminates expensive components such as the compressor diffuser and turbine stator. It also overcomes their related losses and enables efficient cooling of the turbine, he says. Joseph Maayan, former director general of the Israeli defence ministry and the company's chairman, says a technology demonstrator is already working and the "results are very encouraging".
The design can be used in turboshaft, turbojet and turbofan engines, says R-Jet. The company claims an OCN turboprop rated at 640shp (480kW) will have a thermal efficiency of 32%, compared with 23% for a conventional turboprop. Fuel consumption will be 0.43lb/shp/h (262g/kWh) compared with 0.63-0.65 for current engines, it adds.
Several major engine manufacturers are in negotiations to use the technology, says R-Jet. Talks with Pratt & Whitney did not result in an agreement, the company says, because of a demand for marketing exclusivity. "We are in serious talks with a number of potential investors. With another $25 million we can offer a series-production OCN engine in three years," says Maayan.
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Source: Flight International
