In cooperation between Siemens and MAN GHH an industrial gas turbine with an ISO rating of 9.2 5 MW was equipped with a dry low NOx combustion system. Using the hybrid burners of Siemens gas turbines, a new combustion chamber was developed for the gas turbine THM 1304 of MAN GHH. This gas turbine has two V-like arranged combustion chambers, which allow a redesign of the combustion chamber, without changing the remaining parts of the gas turbine and its casing. So it is possible as well, to fit present machines with new combustion chambers. The combustion chambers contain flame tubes of Siemens technology with ceramic tiles and the well proved hybrid burners. After calculation and design the air flow was examined in an isothermal flow model. Finally two prototypes of the combustion chamber mounted on a THM 1304 gas turbine were tested at the MAN GHH gas turbine test bed. Success came very quickly and the test runs are finished now. So for the first time the transfer of the well-known low emission values of the Siemens large scale gas turbines succeeded to an industrial gas turbine of the 10 MW class.

To reduce gas turbine exhaust emissions the combustion system of the MAN GHH industrial gas turbine THM 1304 (ISO power 9250 kW) has been modified. The two outboard combustors in a V–configuration enabled to enlarge the chambers and thus to increase the retention time. Compared to the initial design the nature of combustor exit flow is considerably changed to an additional swirling flow. To estimate the effects of these flow conditions on gas turbine performance the flow towards the high pressure turbine should be investigated. For that purpose a numerical flow simulation in the casing between the combustion chambers and the high pressure turbine nozzles has been accomplished. A Navier–Stokes–Solver (Finite Element Method) has been applied to the computation of the threedimensional turbulent flow. The essential results, especially the flow conditions in front of the HP–turbine nozzles are presented with respect to the idealized combustor exit flow conditions. Besides the swirl strength, the direction of rotation and the swirl relation are varied. It is shown, that the flow at HP–turbine inlet is essentially characterized by the mainly centripetally directed combustor exit flow. Dependent on the above mentioned swirl flow parameters the characteristic flow distribution at HP–turbine inlet changes more or less. In the most favourable case the mass flow distribution at HP–turbine inlet varies circumferentially approx. ±14% and in the worst case approx. ±26%. Associated deviations from the ideal axial flow direction of approx. ±30° respectively ±40° are calculated.

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