## 1 Introduction
It was found that the adoption of lateral slots greatly affected the heat transfer distribution, and the heat transfer levels near the lateral slots were improved. [PERSON] et al. [16] investigated the heat transfer performance of trailing edge channels with inclined pin fin arrays. The effects of fin diameter, inclination angle and rotation number were discussed based on the distributions of heat transfer coefficient. [PERSON] et al. [17] experimentally investigated the thermal performance of triple flow passages in the typical blade, and found that the Coriolis force had the reverse effect on the radially inward flow and outward flow. The decrease of channel orientation weakened the heat transfer level. Moreover, a heat transfer correlation was also proposed. Arranging rough structures or turbulators is an important and effective means of heat transfer enhancement, and has been widely applied in the heat exchangers, refrigeration, electronic component cooling, etc. Therefore, in trailing edge cooling, a large number of researches have focused on the arrangement of turbulators in the internal channels to obtain better heat transfer performance. [PERSON] et al. [18] summarized the rough structures used in the trailing edge cooling channels, including various ribs, fins, dimples, and composite structures, and whose features and differences in the heat transfer were analyzed in detail. [PERSON] et al. [19] compared the cooling performance of rectangular and trapezoidal channels, taking into account the effects of lateral extraction and V shaped ribs. The results showed that the heat transfer coefficient around the lateral slots was significantly improved. [PERSON] et al. [20] investigated the flow and heat transfer characteristics in the trailing edge channels with two kinds of fin arrangements using liquid crystal thermal imaging technology. It was suggested that arranging ribs in the main channel was more effective than in the outlet area. [PERSON] et al. [21] focused on the U shape cooling channels with trapezoidal cross-sections, and carried out CFD (Computational Fluid Dynamics) calculations. They found that the introduction of guide ribs changedthe local flow structures and enhanced heat transfer by 40%. [PERSON] et al. [22] proposed a rectangular cooling channel with longitudinal crossed ribs, and numerically investigated the thermal performance within the _Re_ range of 10,000-30,000. It was concluded that the heat transfer improvement benefited from the secondary flow generated by the rib intersection. [PERSON] et al. [23] arranged dimple structures on the endwalls of two-pass trailing edge channels, and discussed the effects of dimple arrangement on the heat transfer. In order to further improve the cooling performance in the trailing edge, composite cooling technologies based on various cooling methods have become a research hotspot. [PERSON] et al. [24] experimentally and numerically investigated the impingement cooling performance in the trailing edge channels with ribs, and analyzed the effects of jet angle and _Re_. [PERSON] et al. [25] constructed cooling channels with fin-dimple/protrusion composite structures, and concluded that, after numerical investigations, the increase in the dimple/protrusion depth was helpful to improve the heat transfer enhancement. Furthermore, [PERSON] et al. [26] numerically investigated the cooling performance of perforated blockages with inclined holes, and found that the cooling technology greatly improved heat transfer while producing high flow resistance. According to the above literature review, a large number of researches on the trailing edge cooling performance have been conducted, and have covered various aspects, effectively promoting the development of blade cooling technology. In the actual operation of blade trialing edge, the channel outlet configuration is flexible and variable, which has a great influence on the flow and heat transfer characteristics, while this has been rarely investigated.