This study presents an experimental investigation on the effects of nozzle clocking in a 2-stage low pressure turbine. The objective was to incorporate the clocking test results into a new turboshaft engine. The test turbine was manufactured with the same aero geometries between the transition duct of the turbine inlet and the exit expansion duct as that of the development engine and it was tested under the same engine representative conditions. Two miniature Cobra probes were used to measure the turbine inlet and exit flow, both circumferentially for 30° and radially over the range of 2% ～ 98% span. Furthermore, six arc-type rakes with 54 Kiel heads were used to measure the total temperature and total pressure at the exit of the second stage. The measurements were performed for four different nozzle clocking positions. The overall efficiency was evaluated in three different ways, including mechanical and thermodynamic methods. All three methods produced identical clocking positions, in order from the best position to the worst. The overall change in the mechanical and thermodynamic efficiency as measured by probe traverse, as well as the thermodynamic efficiency measured by the rakes, were 0.69%, 0.77%, and 0.42%, respectively. The distribution of efficiency across the span showed that clocking affects the efficiency differently in radial positions and a phase shift of the best clocking position to the next adjacent clocking position was observed. The efficiency change due to clocking was found to be related to the deviations in both the time-averaged velocity and in the total pressure at the exit of the second rotor. This deviation is a result of the relative location of the wake package originating from the first nozzle with respect to the leading edge of the second nozzle.
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