The paper presents the results of measurements carried out in the GTM400 turbojet engine with a changed combustion chamber geometry. The available publications lack more detailed information on the temperature distribution in evaporators, which are part of the combustion chamber of small turbojet engines. As the results of the analysis showed, this is not simple, because the research takes place in very small spaces. The reason for the work carried out is to check whether the temperatures in the evaporators are high enough. This allows to determine whether the fuel is evaporating properly. Therefore, an analysis was carried out to determine the temperature distribution in the area of the inlet to the evaporator. Thanks to the modification of the combustion chamber, it was possible to measure temperatures, which in the engine literature are simulated using numerical analysis. The analysis described in the paper is one of the stages of preparing the engine for operation with hydrogen. It is modified as part of a project to build a hybrid engine burning traditional JET-A1 fuel and alternative fuel, i.e. hydrogen.

In response to the problems of high-temperature gas intrusion and ablation in the expansion slit between ceramic tiles under complex flow conditions in the floating-wall combustion chamber, as well as the issue of hooks exceeding their service temperature, numerical simulations and analysis were conducted for this paper. The study revealed the mechanisms of gas intrusion and sealing and proposed two evaluation metrics for evaluating the cooling effect: the maximum temperature of the hook and the proportion of high-temperature area on the sidewall of the tile. Furthermore, the CRITIC weighting method was used to analyze the weight of these metrics. Based on this, the spacing, radius, and length effects on sealing and cooling effectiveness were studied, and multi-parameter calculations and optimization were performed. The results showed that the degree of gas intrusion in the transverse slit was significantly higher than that in the longitudinal slit. In addition, the sealing method of the jet impingement could effectively cool the downstream of both the transverse and longitudinal slit. The spacing of the jet impingement holes had the greatest impact on the cooling effect, followed by the radius and length. Finally, when the spacing of the holes is 10 mm, the length is 18.125 mm, and the radius is 1.6 mm, the cooling effect is optimal, with the proportion of high-temperature area on the side wall of the tile being 20.86% and the highest temperature of the hook reaching 836.02 K.

The present study involves computational investigation of effusion cooling over a flat plate through the different shaped holes. The interaction between the film jet and the mainstream flow creates a counter-rotating vortex pair, resulting jet detachment from the surface and insufficient film cooling coverage over the surface. To enhance the effusion cooling performance, shaped holes are used in place of standard cylindrical holes to reduce the effects of the counter-rotating vortex pair. Two different shaped holes i.e., conical-shaped and fan-shaped holes are used in the investigation and compared to the cylindrical holes. A commercial finite element method package COMSOL Multiphysics 5.5 is used to simulate and analyse the three-dimensional combustor liners of gas turbine. Data is presented for total 10 rows of effusion holes with injection angles 30o at blowing ratios 0.25, 1.0 and 3.2. The shaped holes provide better cooling effectiveness by increasing the lateral spread of coolant over the surface wall. The results show that both the shaped hole geometries can generate additional anti-counter rotating vortex pairs, which contribute to reducing the strength of the counter-rotating vortex pair. The coolant penetration and strong shear zones at the interaction of coolant jet and main stream in shaped holes are greatly reduced in comparison with cylindrical holes. For a low blowing ratio of 0.25, the conical-shaped holes exhibited adiabatic effectiveness that was 25% and 19% greater than the cylindrical and trapezoidal-shaped holes respectively. On the other hand, fan-shaped holes provide enhanced adiabatic effectiveness at increased blowing ratios. At higher value of blowing ratio 3.2, the adiabatic effectiveness increased by 13% compared to cylindrical holes and 4% compared to conical-shaped holes. In addition, velocity profiles and two-dimensional streamlines have been examined in order to study the flow be-havior on the surface.