Two-Stage Evaporative Inlet Air Gas Turbine Cooling

Gas turbine inlet air-cooling (TIAC) is an established technology for augmenting gas turbine output and efficiency, especially in hot regions. TIAC using evaporative cooling is suitable for hot, dry regions; however, the cooling is limited by the ambient wet-bulb temperature. This study investigates two-stage evaporative TIAC under the harsh weather of Riyadh city. The two-stage evaporative TIAC system consists of indirect and direct evaporative stages. In the indirect stage, air is precooled using water cooled in a cooling tower. In the direct stage, adiabatic saturation cools the air. This investigation was conducted for the GE 7001EA gas turbine model. Thermoflex software was used to simulate the GE 7001EA gas turbine using different TIAC systems including evaporative, two-stage evaporative, hybrid absorption refrigeration evaporative and hybrid vapor-compression refrigeration evaporative cooling systems. Comparisons of different performance parameters of gas turbines were conducted. The added annual profit and payback period were estimated for different TIAC systems.

An Investigation in the Numerical Approach to Solve the Heat Transfer Phenomenon in Gas Turbine

The gas turbine engine's extreme conditions need a robust design to produce efficient energy and reliable operation. Flow and thermal analysis are essential for complex aerodynamic and thermodynamic interaction during turbine performance. There is a need to understand and predict the temperature to make the gas turbine engine efficient. This paper will outline the numerical methods applied for primary cooling methods in gas turbine blades. These include impinging leading-edge cooling, internal cooling in the midsection, and pin fin in the trailing edge. The main objective of this paper is to understand the numerical research done on improving gas turbine cooling. The emphasis will be on understanding the present CFD (Computational fluid dynamics) techniques applied for gas turbine cooling and further development. This paper briefly outlines the new conjugate heat transfer based CFD (computational fluid dynamics) modeling techniques that have evolved over the years due to recent computing power development.

(Performance of Gas Turbine Cooling System (Radiator) at PLTGU XYZ against Environmental Air Temperature)

The heat exchanger is an important component in the gas and steam power plant (PLTGU) industry. One of the most important heat exchangers in gas turbine cooling systems is the gas turbine radiator. The gas turbine radiator functions to cool the cooling water, which circulated to various components of the gas turbine by using environmental air as the cooling medium. The purpose of this study was to determine the effect of environmental temperature on the performance of gas turbine radiators and to compare operational data in 2017 with operational data when the study conducted in 2019. Data collected for 3 days with 2-3 hour intervals. Data processing and analysis shows that the higher the ambient temperature, the higher the radiator effectiveness value. Data in 2017 shows the highest average value of effectiveness obtained at an ambient air temperature of 35 ˚C of 71,274%. Meanwhile, data in 2019 shows the highest average value of effectiveness at an ambient air temperature of 35 ˚C of 58,859%. Thus, the average effectiveness value of gas turbine radiators has decreased by 12,415% from 2017 to 2019

Implementation of Wide Diffusion Angle V-Shaped Holes for Gas Turbine Cooling: Design Phase and Numerical Simulation

This paper describes the design process carried out to develop a new hole geometry. This geometry is able to increase the cooling coverage effect on a turbine blade, in order to have a higher efficiency compared to the standard holes. The first step of the activity described is a CFD analysis of the performances of different hole geometries on a flat plate. Starting from the cylindrical holes the performances of several geometries have been compared. This study allowed the determination of the geometrical parameters mostly responsible of the film effectiveness increase. In this way a criterion able to optimize the hole geometry has been found. Keeping as constraint the same inlet section for all the geometries, the shape of the outlet section was modified in order to maximize the film coverage performances. An optimized hole geometry had been determined. This solution, called V-Shaped hole is characterized by a wide lateral expansion angle and a negligible laidback angle and it is able to increase the cooling effectiveness compared to cylindrical and shaped holes with typical expansion angles (lateral and laidback about 10°). Finally, a comparison with an experimental campaign has been performed to confirm the main results of the CFD analysis.

Flow Visualization of Microscale Effusion and Transpiration Cooling on Semi-cylinder for Gas Turbine Cooling Application

Effusion and transpiration cooling can be an attractive method of air cooling for the next generation high-efficient gas turbine which has a very hot gas temperature over 1,600°C (TRIT). For higher effectiveness of air cooling for a gas turbine vane and blade, the air-cooled flow through effusion-holes and porous metal surface should not penetrate into the mainstream flow but still remain within the thermal boundary layer. The present visualization study examines flow behavior of microscale effusion and transpiration cooling on semi-cylinder. The secondary flow issued from the effusion-holes and porous metal surface is visualized by a smoke-tube method which consists of oil droplet generator, diode pumped solid state (DPSS) laser and highspeed imaging. The flow visualization of microscale effusion and transpiration cooling on semi-cylinder is characterized with various blowing ratios. It is found that the transpiration cooling consumes less coolant air than effusion cooling and has better cooling effectiveness based on the same flow rate of coolant air. Visual criteria can be provided to maintain the effusion and transpiration cooling on semi-cylinder for gas turbine cooling application. [This work was supported by the National Research Council of Science and Technology (NST) grant funded by the Ministry of Science and ICT, Korea (Grant No. KIMM-NK219B).]