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Powerful, smooth, compact and light combined with multi-fuel capability are the main features of the rotary engine. The Wankel engine superb power-to-weight ratio and reliability make it not only suitable for automobile application, but also particularly well suited to aircraft engine use and it can replace the reciprocating piston engine in many areas of use such as sport cars, motorcycle, boats, and small power generation units etc. Since the physics that taking place inside Wankel engine combustion chambers are exceedingly complex, a numerical CFD studies were obtained to understand the unsteady, multidimensional fluid flow and fuel-air mixing inside the combustion chamber of the Wankel rotary engine during the intake and compression cycles. The effects of the engine combustion chamber design and operating parameters on fluid flow and fuel-air mixture formation were investigated: engine velocity, direction of fuel injection into the combustion chamber, with emphasize on diesel and hydrogen injection fuels. The injector nozzle size, injected fuel velocity, the position of injector and angle of injection were also investigated.
A computational tool and a methodology for steady state heat exchanger simulations of recuperated gas turbines and aero-engines have been developed. As an example a compact tube bundle heat exchanger with oval shaped tubes was chosen. The simulation tool proved to work for different layouts of the heat exchanger and for different geometrical configurations of the gas turbine engine exhaust ducts. The resistance tensors were tuned against both CFD-data and experimental data and the computational model was to some extent validated against experimental results. For the validation isothermal experimental data from the Laboratory of Fluid Mechanics and Turbomachinery at the Technical University of Thessaloniki was used together with hot gas channel data from MTU. The calculated and measured velocity profiles showed an acceptable agreement that in some of the cases was even very good. The calculated pressure drop deviated less than 10% for the compared cases, which must be considered to be acceptable. The calculared results for the hot gas cases showed an exaggerated heat transfer rate, most likely due to the use of a cold side heat transfer correlation for fully turbulent flow, although the Reynolds numbersindicated transitional flow.