An Axial Turbobrake

Goodisman, M. I.; Oldfield, M. L. G.; Kingcombe, R. C.; Jones, T. V.; Ainsworth, R. W.; Brooks, A. J.

doi:10.1115/91-gt-001

Cited by 4 publications

(7 citation statements)

References 5 publications

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“…For the experiments described in this paper, only the HP stage was installed. A novel feature of the facility is the aerodynamic turbobrake [6], which is on the same shaft as the turbine and is driven by the turbine exit-flow. At the design speed, the turbobrake power is matched with the turbine, and thus constant speed is maintained during a run.…”

Section: Description Of the Facilitymentioning

confidence: 99%

A hot-streak (combustor) simulator suited to aerodynamic performance measurements

Povey

Qureshi

2008

Proceedings of the Institution of Mechanical Engineers, Part G:

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A new hot-streak (combustor) simulator has been designed and implemented in a turbine test facility at QinetiQ Farnborough (the QinetiQ Isentropic Light Piston Facility, ILPF) to study the impact of temperature distortion on high pressure (HP) turbine efficiency, aerodynamics, and heat transfer. The ILPF is an engine scale, short duration, rotating transonic turbine test facility, in which M , Re, T g /T w , and N / √ T are matched to engine conditions. The research forms part of the EU Turbine Aero-Thermal External Flows (TATEF II) programme.The hot-streak simulator is a second-generation design, in which cold gas is introduced into a hot mainstream though radial and circumferential slots upstream of the turbine stage. The simulator is rotatable, so the effect of clocking (relative circumferential position of hot streak and nozzle guide vane leading edge) can easily be investigated. An emphasis was placed on accurate measurement of turbine inlet enthalpy flux so that the impact of hot streaks on turbine efficiency could be investigated.The hot-streak simulator differs from all previous systems in that a pronounced radial and circumferential temperature profile has been generated, with a hot-streak to vane count of 1:1. The profile is very well matched (non-dimensionally) to the target profile, which is a combustor temperature profile measured in a modern operating engine at the most extreme point in the cycle. The most accurate area survey of a simulated temperature profile has been conducted to date, and this demonstrates that the simulator offers an exceptionally high degree of circumferential symmetry and run-to-run repeatability.The design and commissioning of the simulator is described, and the measured temperature profiles are compared with the target profile.

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Section: Description Of the Facilitymentioning

confidence: 99%

A hot-streak (combustor) simulator suited to aerodynamic performance measurements

Povey

Qureshi

2008

Proceedings of the Institution of Mechanical Engineers, Part G:

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“…The downstream throat was then set to give the correct turbine pressure ratio at the start of the run The turbobrake bypass shutters were opened in stages, and the speed decay reduced. As predicted by , Goodisman et al (1992), it proved necessary to install a 12.5% downstream blockage ring together with some bypass flow to match the turbobrake to the turbine. The adjustment of the bypass to reduce the speed change to less than 1% during the run proved to be simple and progressive.…”

Section: Commissioningmentioning

confidence: 96%

“…Brakeless, inertial containment has been successfully used (Ainsworth et al, 1988), but the rotor speed then increases during the run and for this facility a massive flywheel would be required to keep the increase in check. Goodisman, et al (1992) surveyed the braking systems (dynamometers) then available and concluded that the most suitable was the new, patented, axial turbobrake.…”

Section: Turbobrakementioning

confidence: 99%

“…The principles of the axial turbobrake have been previously described (Goodisman et al, 1992;Goodisman, 1991) and are only outlined here. The turbobrake consists of a second disc mounted on the turbine shaft ( Figure 2), with blading in the turbine exit flow.…”

Section: Turbobrakementioning

confidence: 99%

“…Earlier tests (Goodisman et al, 1992) using a 17% scale model running at the correct Reynolds number and dimensionless speed showed that the concept worked, and that the turbobrake stage loading of -2 was more than enough to absorb the ILPF turbine power. It was also demonstrated that the turbobrake power could be adjusted by a combination of bypass and downstream blockage.…”

Section: Turbobrakementioning

confidence: 99%

See 2 more Smart Citations

Installation of a Turbine Stage in the Pyestock Isentropic Light Piston Facility

Hilditch¹,

Fowler

Jones

et al. 1994

Volume 4: Heat Transfer; Electric Power; Industrial and Cogeneration

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The Isentropic Light Piston Facility (ILPF) at Pyestock has been upgraded to include a single stage, high pressure turbine. All major non-dimensional parameters are accurately scaled during the 0.4s run time, enabling heat transfer and aerodynamic measurements to be made at engine representative conditions. The ILPF was previously an annular cascade facility. This paper describes the design and integration of the rotor module and the results of the commissioning tests. An important feature is a novel, patented, turbobrake which is shown to maintain the turbine at a constant speed during the run.

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Heat transfer measurements on an intermediate-pressure nozzle guide vane tested in a rotating annular turbine facility, and the modifying effects of a non-uniform inlet temperature profile

Povey

Chana

Jones

2003

Proceedings of the Institution of Mechanical Engineers, Part A:

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In modern gas turbine engines there exist significant temperature gradients in the combustor exit flow. These gradients arise because both fuel and dilution air are introduced within the combustor as discrete jets. The effects of this non-uniform temperature field on the aerodynamics and heat transfer rate distributions of nozzle guide vanes and turbine blades is difficult to predict, although an increased understanding of the effects of temperature gradients would enhance the accuracy of estimates of turbine component life and efficiency. Low-frequency measurements of heat transfer rate have been conducted on an annular transonic intermediate-pressure (IP) nozzle guide vane operating downstream of a high-pressure (HP) rotating turbine stage. Measurements were conducted with both uniform and non-uniform inlet temperature profiles. The non-uniform temperature profile included both radial and circumferential gradients of temperature. Experiments were conducted in the isentropic light piston facility at QinetiQ Pyestock, a short-duration engine-size turbine facility with 1.5 turbine stages, in which Mach number, Reynolds number and gas—wall temperature ratios are correctly modelled. Experimental heat transfer results are compared with predictions performed using boundary layer methods.

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An Axial Turbobrake

Cited by 4 publications

References 5 publications

A hot-streak (combustor) simulator suited to aerodynamic performance measurements

A hot-streak (combustor) simulator suited to aerodynamic performance measurements

Installation of a Turbine Stage in the Pyestock Isentropic Light Piston Facility

Heat transfer measurements on an intermediate-pressure nozzle guide vane tested in a rotating annular turbine facility, and the modifying effects of a non-uniform inlet temperature profile

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