Rolls-Royce Holdings

About: Rolls-Royce Holdings is a company organization based out in Derby, United Kingdom. It is known for research contribution in the topics: Turbine & Gas compressor. The organization has 4027 authors who have published 6305 publications receiving 80517 citations. The organization is also known as: Rolls-Royce Holdings plc.

The Effect of Blade Tip Geometry on the Tip Leakage Flow in Axial Turbine Cascades

Abstract: The phenomenon of tip leakage has been studied in two linear cascades of turbine blades. The investigation includes an examination of the performance of the cascades with a variety of tip geometries. The effects of using plain tips, suction side squealers, and pressure side squealers are reported. Traverses of the exit flow field were made in order to determine the overall performance. A method of calculating the tip discharge coefficients for squealer geometries is put forward. In linking the tip discharge coefficient and cascade losses, a procedure for predicting the relative performance of tip geometries is developed

Shaft power transfer in gas turbine engines with machines operable as generators or motors

Abstract: A multispool gas turbine engine for an aircraft application includes a transmission system which is operative to transfer power between relatively rotatable engine spools. In a first mode the transmission system is operative to transfer power from the engine's low pressure spool to its high pressure spool and thereby improve the engine's in-flight relight characteristics; in a second mode it is operative to transfer power from the engine's intermediate pressure spool to its high pressure spool to improve engine part speed performance; and in a third mode to transfer power from the engine's high pressure spool to its intermediate pressure spool to assist in ground starting. With each shaft is an associated flow displacement machine (64,66,62) operable as a pump or motor. In other embodiments, a differential is employed for the power transfer between spools.

Nonaxisymmetric Turbine End Wall Design: Part II—Experimental Validation

Abstract: The Durham Linear Cascade has been redesigned with the nonaxisymmetric profiled end wall described in the first part of this paper, with the aim of reducing the effects of secondary flow. The design intent was to reduce the passage vortex strength and to produce a more uniform exit flow angle profile in the radial direction with less overturning at the wall. The new end wall has been tested in the linear cascade and a comprehensive set of measurements taken. These include traverses of the flow field at a number of axial planes and surface static pressure distributions on the end wall. Detailed comparisons have been made with the CFD design predictions, and also for the results with a planar end wall. In this way an improved understanding of the effects of end wall profiling has been obtained. The experimental results generally agree with the design predictions, showing a reduction in the strength of the secondary flow at the exit and a more uniform flow angle profile. In a turbine stage these effects would be expected to improve the performance of any downstream blade row. There is also a reduction in the overall loss, which was not given by the CFD design predictions. Areas where there are discrepancies between the CFD calculations and measurement are likely to be due to the turbulence model used. Conclusions for how the three-dimensional linear design system should be used to define end wall geometries for improved turbine performance are presented.