Fixed Blade Leakage Flow Guide Vane for Rotary Machine Efficiency
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Solution Overview
Problem
In rotary machines, such as steam turbines, leakage flows of high-pressure working fluid into axial gaps and re-enter the primary fluid path at a different angle, leading to efficiency losses and increased operating expenses due to the deflection by stationary and rotating components.
Innovation Solution
The implementation of a fixed blade with a leakage flow guide vane assembly that induces a tangential or swirl velocity to the leakage flow, matching the velocity of the primary flow path, thereby aligning the angle of incidence and reducing efficiency losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If axial gaps are defined between stationary and rotating components to facilitate rotation, then rotational movement is enabled, but working fluid leaks into the gaps and creates efficiency losses
Solution Approach 1:
Guide vanes are introduced as intermediary components between the stationary and rotating parts. These guide vanes redirect the leakage flow and impart tangential velocity to the working fluid, causing it to re-enter the primary flow path at the correct angle and reduce incidence losses on rotor blades
2Quantity of substance
If leakage flow is allowed to enter the primary fluid path, then fluid continuity is maintained, but the angle of incidence increases and creates efficiency losses
Solution Approach 1:
The guide vanes change the flow parameters of the leakage stream by imparting tangential velocity and redirecting it. This modifies the angle of incidence and velocity vector of the leakage flow so that when it re-enters the primary path, it matches the flow conditions and does not cause efficiency losses
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 solution enhances the overall efficiency of the rotary machine by reducing the incidence loss of the steam leakage flow on downstream rotor blades, resulting in decreased fuel costs and improved operational efficiency.
Implementation Method 1
a leakage flow guide vane assembly (200, 400) coupled to a downstream portion of the fixed blade (26) and oriented to induce a tangential or swirl velocity to a leakage flow of steam
Data Source
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AI summary
A fixed blade (26) for a rotary machine includes an airfoil (44), a stationary portion (42) coupled to a radially inner end of the airfoil (44), and a leakage flow guide vane assembly (200) coupled to the stationary portion (42). The leakage flow guide vane assembly (200) includes a plurality of passages (203) defined therein. The passages (203) are oriented to induce a swirl velocity to a working fluid flowing through the passages (203). A method of assembling a rotary machine comprises: coupling a fixed blade to a diaphragm of a casing of the rotary machine; coupling a rotor, that includes at least one turbine stage (12) located adjacent to and downstream from the fixed blade (26), to the casing; forming a primary flow path within the casing and in flow communication with an inlet of the casing; and coupling a leakage flow guide vane assembly (200) to the fixed blade (26) adjacent the at least one turbine stage, wherein the leakage flow guide vane assembly (200) is positioned in a leakage flow path defined between the rotor and the fixed blade (26) for inducing a swirl velocity in a working fluid passing through the leakage flow path. A rotary machine comprises a rotor and a blade (26) that extends circumferentially about said rotor; said blade (26) comprises an airfoil (44) and a stationary portion (42) coupled to a radially inner end of said airfoil (44) and defining a leakage flow path between said stationary portion (42) and said rotor.