Steam Turbine Exhaust Chamber Protruding Portion Vortex Control
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Solution Overview
Problem
The existing steam turbine exhaust chamber designs face challenges in suppressing the increase in pressure loss in the diffuser flow passage due to the intrusion of vertical vortices, which leads to performance deterioration.
Innovation Solution
The design incorporates a protruding portion on the side wall surface of the casing, positioned radially outward from the downstream end of the flow guide, to deflect vertical vortices away from the diffuser flow passage, thereby reducing pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a guide plate structure protruding inward from the steam turbine exhaust chamber wall surface is provided to suppress reverse flow, then reverse flow suppression is improved, but vertical vortex intrusion into the diffuser flow passage is not effectively suppressed and pressure loss increase is limited
Solution Approach 1:
The invention divides the flow control function into two separate structures: a guide plate for suppressing reverse flow and a protruding portion for suppressing vertical vortex intrusion. This segmentation allows each structure to specialize in one function, improving overall effectiveness without interfering with the other.
Solution Approach 2:
The protruding portion extends in the radial direction outward from the side wall surface, creating a three-dimensional flow control structure that addresses vertical vortex intrusion from a different spatial dimension than the guide plate, thereby effectively blocking vortex intrusion into the diffuser flow passage.
2Object-affected harmful factors
If the effective flow-passage area of the diffuser flow passage is reduced due to steam flow backward along the bearing cone, then reverse flow is suppressed, but pressure loss increases and performance deteriorates
Solution Approach 1:
The protruding portion acts as an intermediary structure between the side wall surface and the diffuser flow passage, intercepting vertical vortices before they can intrude into the flow passage and cause pressure loss, thereby protecting the diffuser flow passage without reducing its effective area.
3Stability of the object's composition
If vertical vortex falls from the upper section of the steam turbine exhaust chamber, then natural flow pattern is maintained, but reverse flow is generated along the bearing cone and performance deteriorates
Solution Approach 1:
The protruding portion is positioned to preemptively intercept vertical vortices falling from the upper section before they can reach the diffuser flow passage and generate reverse flow, applying counter-action in advance to prevent the harmful effect.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively suppresses the intrusion of vertical vortices into the diffuser flow passage, leading to improved performance and reduced pressure loss in the steam turbine exhaust chamber.
Implementation Method 1
a vertical vortex falling from the upper section of the steam turbine exhaust chamber may cause generation of a reverse flow in the steam flow along the bearing cone
Implementation Method 2
the flow guide forming a diffuser flow passage between the flow guide and the bearing cone
Data Source
AI summary
A steam turbine exhaust chamber for guiding steam after passing through a rotor blade of a final stage of a steam turbine to outside of the steam turbine includes: a casing; a bearing cone; and a flow guide. An inner surface of the casing includes an inner circumferential surface extending along an axial direction of the rotor at a radially outer side of the flow guide and a side wall surface connecting the inner circumferential surface and the bearing cone. A first protruding portion is formed on the side wall surface along the circumferential direction above a horizontal plane including a rotational axis of the rotor. The first protruding portion is positioned at an outer side, in the radial direction of the rotor, of a downstream end of an inner circumferential surface of the flow guide in at least a partial range in the circumferential direction.