Thermodynamic Study of Improving Efficiency of a Gas Turbine Locomotive

Although railroad electrification has multiple benefits and is one of the global initiatives to promote transportation sustainability, 50% of the railroads are still off the electrical grid. Use of the gas turbine as a source of mobile electricity is one of the promising technologies, crucial for the transition to electrical traction. This paper is a part of the project of PSC KUZNETSOV on developing the gas turbine locomotive. Current issues include low performance and resulting high exhaust temperature. These issues are because of high hydraulic losses due to the limited roof area used for the air intake. Aim of this work is to find optimal thermodynamic operation point which provides efficiency boost, lower exhaust temperature and requires least alterations to the design. This data will be the basis for the next stages of development, including optimization of the turbomachines and structural design for strength improvement. This study used the numerical simulation of the thermodynamic behavior of the gas turbine power plant. Firstly, the virtual model of the engine was developed using the CAE-system ASTRA and the parameters of the engine provided by the PSC KUZNETSOV. Secondly, model adequacy was assured using the experimental data on climatic characteristics of the gas turbine power plant. The third step was to investigate how would removing the first one, two or three stages of the low-pressure compressor alter its characteristics, and the performance of the engine. Altered low-pressure compressor (LPC) required adjustments of the operating points of all turbines, so this issue was addressed at the next step. Finally, the thermodynamic characteristics of the power plant were calculated using the optimized compressor (three- and four-stage variants) and turbine. Optimization aimed at keeping target performance indicators while providing lower air flow rate and decreased exhaust temperature. It also included restrictions on the rotational speeds, geometry and other parameters to keep the stress-strain state of the engine elements close to the baseline. The results of this research show two promising solutions for the 6MW and 8.3MW variants of the power plant having air flow rates 27 and 17 percent lower than the baseline, respectively. The results of this study would be used to design the altered engine components: optimize blade geometry and strength of the critical elements of the engine.