The gas traction turbine has made it possible to construct turbotrains through its high power-to-weight ratio an its compactness. The essential features of this turbotrains are their great operating stability and their low requirement in terms of infrastructure, this being obtained through a general weight reduction of the motor vehicles which itself results from the lightness of the drive system. This has made it possible to achieve performances in thermic traction on a level with those achieved on the main electrified lines, in spite of the generally more unfavorable configuration of the infrastructure in the non-electrified network. A large increase in passenger traffic resulted from this on the lines served by turbotrains (70 % to 115 %). However, from 1973 onwards, the sharp increase in the price of energy had a harmful effect on the economic statement for this type of traction, as the first model of gas turbine has a specific fuel consumption higher than that of the diesel engine. In fact, study of the thermodynamic cycle shows that the gas turbine can reach at its nominal rating, the energy efficiency of this engine as soon as technological and metallurgical progress makes it possible to increase the compression ratio and efficiency sufficiently, as well as the inlet temperature of the first stage of the HP turbine (TIT). This assertion has been checked with high-power aircraft turbo-engines. In the case of 1000/1500 kW machines used for railway traction, conditions are less favorable, but it is nevertheless possible to make distinct progress in relation to the present situation, even if the TIT increase must be limited in order to ensure good endurance, taking into account the limitations and requirements of railway service. In this case, the main factor in progress is increase of the pressure ratio and then, in the second stage, use of a heat exchanger. According to these two stages, the pressure ratio must approximately correspond 'in-fine' to the optimum value which gives maximum efficiency and possibilities for the exchanger cycle and future progress in the turbine as regards compression efficiency and TIT increase. This is the case with the new Turbo XII 1200 kW turbo-engine tested by SNCF since August 1977. This has already made it possible, in the first stage (without exchanger), to record a 20 % saving on the traction fuel consumtion. In this stage, this consumption (expressed in litre per seat-kilometer offer) is lowered practically to the level of that of a diesel rail-car.
L'amelioration de rendement energetique de la turbine a gaz de traction resultats obtenus avec le nouveau turbomoteur Turmo XII
Verbesserungen an Gasturbinen für Lokomotivantriebe
Improvement of the energy output of the gas turbine in rail traction and results obtained with the new Turmo XII turbomotor
1979
28 Seiten, 9 Bilder, 3 Tabellen
Conference paper
Storage medium
French
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