## 1 Introduction
[14] studied the heat transfer of impingement cooling at the leading edge of turbine vane by using transient liquid crystal thermal imaging technology, and found that the \(Nu\) and pressure drop increased with the increase in the \(Re\); The biased impingement holes increases the average Nusselt number of the internal surface, reduces the resistance coefficient and significantly improves the heat transfer uniformity. [PERSON] et al. [15] investigated the effects of nozzle shape and different inlet conditions on the \(Nu\) distribution on the concave cylindrical surface of the channel in the leading edge of the turbine vane, and found that after rounding the nozzle holes, there is a larger stagnation zone in the channel and the maximum \(Nu\) decreases. [PERSON] et al. [16] found that the curvature of the target plate has no significant effect on the flow and heat transfer. [PERSON] et al. [17] used Particle Image Velocimeter and Laser Doppler Velocimeter to monitor the impingement cooling. The \(Re\) has little effect on the field, and the length of the jet core area depends on the distance between the nozzle and the impingement cooling surface. [PERSON] et al. [18] investigated impingement cooling by combining numerical simulation with experiment. With the increase in the \(Re\) and the decrease in plate spacing-impingement hole diameter ratio, the \(Nu\) of the impact zone increased. [PERSON] et al. [19] found that when the hole spacing is small, the impingement cooling is more sensitive to the relative position of film holes and impingement holes. [PERSON] et al. [20] analyzed the impingement cooling of the turbulent circular jet by combining numerical simulation with experiment. The \(Nu\) of the target plate increases with the decrease in the ratio of impingement hole-target plate distance to impingement hole diameter, especially in the impacted area. Turbulence structure in the leading edge of gas turbine guide vanes can enhance the flow field disturbance and improve the heat transfer. Adding pin fins can also increase the structural strength of the vane [21]. [PERSON] et al. [22] studied the flow and heat transfer for array impingement cooling system with micro rectangular pin fins, and found that the heat transfer significantly enhanced under the influence of micro pin fins. [PERSON] et al. [23] found that the heat transfer of turbine vane with spoiler ribs and guide vane is more uniform and the pressure drop of cooling channel is significantly reduced by using the method of numerical simulation and experiment. [PERSON] et al. [24] analyzed the physical quantities of the flow field in different channels with pin fins, such as the average velocity, the Reynolds stress tensor and the \(Nu\) distribution on the model surface. The optimization height of pin fins depends on the turbulence model. [PERSON] et al. [25] designed a new beveled pin fin based on airfoil profile, and this pin fin can produce lasting and stable longitudinal vortices to strengthen the disturbance of flow field, yielding a good effect on enhancing heat transfer of the cooling channel. [PERSON] et al. [26] investigated the influence of the arrangement of pin fins on impingement cooling. The total heat transfer of the best arrangement of pin fins is about four times larger than that of the smooth channel. [PERSON] et al. [27] investigated the heat transfer characteristics of impingement cooling systems with diamond, cubic, circular and elliptic pin fins. The circular pin fins can be the best choice among the shapes studied by analyzing the \(Nu\) of the impact target surface. [PERSON] et al. [28] found that the elliptical pin fins can reduce the local temperature in the stagnation zone and jet zone, and the average Nusselt number of the target plate is increased by about 47-54% compared with that without pin fins. [PERSON] et al.