Accurate predictability of high-pressure turbine nozzle guide vane aero-thermal performance is highly desired in the development campaign due to the exposure of the component to a frequent and high heat load. In this paper, the representative vane profile in modern aero-engines is numerically studied. Aerodynamics and aero-thermal validations of the blade profile have been performed in comparison with the available experimental data. It has been shown that a satisfactory agreement could be achieved with the use of the transitional turbulence model shear stress transport γ–θ due to its superiority in capturing the laminar–turbulent transition. Sensitivity studies on the increase in the inlet turbulence intensity, inlet endwall boundary layer thickness, and inlet total temperature profile have been performed to understand the impact of inflow conditions’ uncertainty on the aero-thermal predictability. Increasing the inlet turbulence intensity increases the pressure surface heat transfer coefficient and induces an earlier transition onset on the suction surface. Due to the rapid decay of turbulence intensity in the numerical model, the use of an artificially high inlet turbulence intensity has been shown to be effective in the prediction improvement. On the other hand, the change in the inlet boundary layer thickness influences the formation and strength of the secondary flow, namely, horseshoe vortex and passage vortex. These secondary flow phenomena affect the local blade surface heat transfer coefficient in the near-endwall region although the most significant rise in heat transfer is found on the endwall. The temperature distortion amplitude of a hot streak and its relative clocking position with the vane significantly affect the heat flux distribution. In contrast, the heat transfer coefficient is less sensitive to the change in hot streak conditions. However, it has been shown that increasing the temperature distortion amplitude could induce a larger difference among different clocking configurations. In addition, decreasing the difference between the fluid and wall temperature would delay the transition onset and stabilize the boundary layer. Further analysis of the unsteady effects has been carried out by comparing the steady and time-averaged flow solutions. It has been observed that the discrepancy between these solutions is attributed to the flow field nonlinearity. Thus, a significant discrepancy can be found in the laminar–turbulent transition as well as in the trailing edge region. However, since the contribution of these regions on the total area-averaged heat transfer is small, their influence on the total vane heat transfer is limited.

A drone delivery system, characterized by its low energy consumption, high efficiency, and extensive coverage capability, has been adopted as an effective solution to overcome the limitations of traditional ground transportation. However, due to strong interactions between urban structures and wind, the wind environment in the low-altitude airspace of urban areas poses significant safety risks for drone operations, a challenge that remains unresolved. To mitigate these risks, this study presents a methodology for precisely defining the no-fly zones (NFZs) for drone operations using computational fluid dynamics (CFD) simulations. Three hazardous indices—safe, deviation, and unsafe—are proposed to indicate the drone operation status. High-resolution CFD models of urban wind environments in a real city area are coupled with meteorological wind data to provide statistical results for the three indices. The Reynolds-averaged Navier–Stokes turbulence model is employed to simulate two wind environments, standard wind and strong wind, under 36 incoming flow directions. Considering eight flight orientations of drone operating in horizontal planes at various heights, a set of maps for the occurrence probability of the three hazardous indices is provided. These maps can be utilized to determine safe areas, identify no-fly zones corresponding to high occurrence probabilities of deviation and unsafe indices, and establish efficient flight paths for drone operations.

The squealer tip has significant influence on both the aerodynamic and heat transfer characteristics of the high-pressure turbine blade. However, due to the complexity of parameterization and meshing of the squealer and the complicated flow structure within the over-tip region, the existing squealer designs in the open literature have constant squealer heights. In this paper, the design space to the squealer height with non-uniform squealer height is extended and the new flow features it may bring are investigated. A parameterization system specifically designed for the non-uniform squealer height using five control parameters is implemented to automatically generate the geometry and hybrid meshes. Combining it with the multi-objective optimization system using genetic algorithms, a transonic turbine cascade squealer tip is optimized employing Reynolds-averaged Navier–Stokes k–ω shear stress transport model. The main objective of this study is to obtain a squealer configuration with the lowest total pressure loss coefficient and heat transfer coefficient. The optimum configuration with non-uniform squealer height achieves improvements in both the aerodynamic efficiency and the heat transfer performance, relative to the baseline conventional squealer tip geometry with the constant squealer height. Additionally, this work demonstrates that a flow structure in which the main flow forms a “blanket” below the leakage flow in the squealer is beneficial for aerothermal performance, especially reducing heat transfer losses, which provides valuable insight into the squealer tip design of advanced high-pressure turbines.