Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

ROTORSHAFT SHIFT FOR TURBINE NOZZLE CONTROL

IP.com Disclosure Number: IPCOM000241447D
Publication Date: 2015-Apr-29
Document File: 3 page(s) / 62K

Publishing Venue

The IP.com Prior Art Database

Abstract

A system and a technique for optimizing an Organic Rankine Cycle (ORC include axial shifting of shaft to control nozzle or turbine overlap. The shaft is positioned through an active magnetic bearing control. The magnetic bearing control allows continuous change of overlapped cross-section between a nozzle exit and a wheel inlet. The change in overlapped cross-section is observed for throttled, fully open, and bypass nozzle conditions. It is found that a working fluid passes through a suitable passage to a diffuser instead of through vanes of a wheel, for example, over a shroud. The technique allows adapting pressure or mass flow relation in the ORC to optimize performance for a wide range of heat input. The technique simplifies startup and shutdown of the ORC by protecting the turbine from liquid ingression without an external bypass.

This text was extracted from a Microsoft Word document.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 51% of the total text.

ROTORSHAFT SHIFT FOR TURBINE NOZZLE CONTROL

BACKGROUND

The present disclosure relates generally to a turbine generator and more particularly to a technique to optimize performance of an Organic Rankine Cycle (ORC) for a wide range of heat input.

Generally, in an integrated turbine generator, nozzles, a radial turbine wheel, a diffuser and an electric generator are all configured in one hermetic casing. A working fluid after expansion passes over the generator to provide cooling. A turbine wheel and a generator rotor are configured as one continuous shaft.  In such turbine generators, nozzles are choked with a fixed geometry.  Consequently, pressure in Organic Rankine Cycle (ORC) is related to fluid mass flow, where the ORC is based on the turbine generator. Also, flexibility of the cycle in terms of efficient operation under variable heat load is very limited in such geometry. The cycle cannot obtain independent control over turbine inlet superheat and heat source utilization.  Furthermore, for start-up and shutdown of the cycle, two-phase or liquid phase conditions occur at an expander inlet of the turbine generator.  Such conditions damage the turbine when no bypass is used.

Conventional techniques include variable nozzle vanes and an external bypass.  For example, a conventional technique includes a nozzle configuration to prevent occurrence of airflow resistance.  The nozzle configuration includes a throttle on the edge of a nozzle exit for a flow passage.  However, such and other conventional techniques include additional components, which add complexity and cost.

It would be desirable to have a technique to optimize performance of an Organic Rankine Cycle (ORC) for a wide range of heat input.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 depicts a schematic of continuous change of overlapped cross-section between a nozzle exit and a wheel inlet between throttled, fully open and bypass nozzle condition.

DETAILED DESCRIPTION

The disclosed system and technique are useful for optimizing an Organic Rankine Cycle (ORC), which is based on a turbine generator, for a wide range of heat input. The technique includes axial shifting of a shaft to control nozzle or turbine overlap.  The shaft is positioned through an active magnetic bearing control. The magnetic bearing control allows continuous change of an overlapped cross-section between a nozzle exit and a wheel inlet. The change in overlapped cross-section is observed for throttled, fully open, and bypass nozzle conditions. It is found that a working fluid passes through a suitable passage to a diffuser instead of through vanes of a wheel, for example, over a shroud.

Figure 1 depicts a schematic of continuous change of overlapped cross-section between the nozzle exit and the wheel inlet between throttled, fully open, and bypass nozzle conditions.

Figure 1

As depicted in Figure 1 above, (a) is a turbine wheel, (b) is a shaft, (c) is a diffuser, (d) is a magnetic bearing, (e) is a shroud bypass,...