The flow of opposing jets was studied in computational fluid dynamics simulation. To clarify the flow field of the jet engine combustor, it is necessary to study air-jet dilution effects typical of opposing jets. The velocity distribution and turbulence intensity were obtained in large eddy simulation for air and an average Reynolds number of 2 × 10⁴ corresponding to the jet diameter and velocity. Results obtained numerically generally agreed quantitatively with experimental results obtained in our previous study. Simulations were then carried out to clarify the effect of the momentum flux ratio J (4, 9, 16, and 64) on mixing. Unmixedness was found to be highest for J = 4 since the penetrations and thus collision of opposing jets were weak for J = 4. When J = 9, 16, 64, mixing was improved by jet collision. It is proposed that the mixing mechanisms are differed depending on J.

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In order to achieve high process efficiencies for the economic operation of stationary gas turbines and aero engines, extremely high turbine inlet temperatures at adjusted pressure ratios are applied. The allowable hot gas temperature is limited by the material temperature of the hot gas path components, in particular the vanes and blades of the turbine. Thus, intensive cooling is required to guarantee an acceptable life span of these components. Modern computational tools as well as advanced calculation methods support essentially on the successful design of these thermally high-loaded components. The homogeneous, or sometimes also mentioned as “full”, conjugate calculation technique for the coupled calculation of fluid flows, heat transfer and heat conduction is such an advanced numerical approach in the design process and huge experiences on validation and application have been collected throughout the years. This paper summarizes the numerical approach for this method as well as provides a collection of numerical results obtained by the authors for validation cases for a convection-cooled turbine vane test case as well as comparison to calculation data for this test case provided in open literature. Furthermore, systematic studies on the impact of calculation parameters, e.g. hot gas fluid properties, and numerical models for turbulence calculation are performed and the numerical results are compared to the experimental results of the test case.

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The thermodynamic cycle of an intercooled turbofan engine was optimized by considering various characteristics of intercoolers (ICs). Sixty-three intercooled turbofan engines were optimized using an evolutionary algorithm. Thirty-nine design parameters were analyzed using proper orthogonal decomposition, and the effects of the IC performance on the engine thermodynamic cycle were examined. The improvement in net fuel consumption due to intercooling strongly depends on the characteristics of the IC fin, and the net fuel consumption is minimized at a particular fin height. By using ICs with an appropriate fin height, intercooling increases the overall pressure ratio, while increasing the heat transfer surface areas and cross-sectional areas of the ICs realizes high effectiveness and low pressure losses. The pressure ratio partition between the intermediate- and high-pressure compressors is determined according to incompatible characteristics of the IC, such as pressure losses and the temperature difference between the inlet and outlet of the IC. Because the weight of the IC is proportional to its fin area density, increasing the fin area density reduces the net fuel consumption. However, it does not significantly influence the thermodynamic cycle of the engine.

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