Variable Geometry Turbine Inlet Layout for Volute Cross-Talk
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Solution Overview
Problem
In multiple-entry turbines, transient pressure pulses between volutes cause cross-talk, leading to fluid blockages and engine energy losses, which are exacerbated by variable geometry mechanisms due to the presence of a dividing wall.
Innovation Solution
A variable geometry turbine design with a dividing wall tip radius at least 1% larger than the movable wall member's outermost radius within the inlet passageway, ensuring adequate flow and minimizing cross-talk while maintaining engine performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a dividing wall is used to separate volutes in a multiple-entry turbine, then cross-talk between volutes is reduced, but the dividing wall may cause fluid blockages and engine energy losses
Solution Approach 1:
The turbine housing is segmented into multiple volutes separated by a dividing wall, allowing independent flow paths for exhaust gases from different cylinder banks. This segmentation prevents pressure pulses from one volute from directly affecting another, reducing cross-talk while maintaining energy efficiency through proper geometric design of the dividing wall tip radius
Solution Approach 2:
The dividing wall tip radius is locally optimized to be at least 1% larger than the radially outermost part of the movable wall member. This local geometric quality ensures smooth fluid flow around the dividing wall tip, preventing fluid blockages and energy losses while effectively separating the volutes to reduce cross-talk
2Loss of energy
If the dividing wall tip radius is increased to prevent fluid blockages, then engine energy losses are reduced, but the space available for variable geometry mechanism is reduced
Solution Approach 1:
The dividing wall tip radius parameter is specifically designed to be at least 1% larger than the radially outermost part of the movable wall member. This parameter change optimizes the balance between preventing fluid blockages (reducing energy losses) and maintaining adequate space for the variable geometry mechanism to operate effectively
3Power
If variable geometry mechanism is added to optimize turbine performance, then power output is improved, but cross-talk between volutes is exacerbated
Solution Approach 1:
The dividing wall segments the turbine into separate volutes, preventing cross-talk from affecting turbine performance even when the variable geometry mechanism is active. This segmentation allows the movable wall member to adjust the inlet passageway area without causing pressure pulse interactions between volutes
Solution Approach 2:
The specific geometric design of the dividing wall tip radius (at least 1% larger than the movable wall member's outermost radius) creates a local flow optimization that prevents fluid blockages and minimizes cross-talk, allowing the variable geometry mechanism to operate effectively across different power output conditions
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 design reduces cross-talk, maintains even flow through both volutes, and prevents engine braking, while allowing partial blockages to drive exhaust gas recirculation for additional engine functions.
Implementation Method 1
an exhaust gas driven turbine wheel mounted on a rotatable shaft within a turbine housing
Implementation Method 2
The compressor wheel delivers compressed air to the intake manifold of the engine, thereby increasing engine power
Implementation Method 3
providing vanes, referred to as nozzle vanes, in the inlet passageway so as to deflect gas flowing through the inlet passageway towards the direction of rotation of the turbine wheel
Data Source
AI summary
A variable geometry turbine comprising: a wheel supported for rotation about an axis; a housing comprising a first volute for receiving gas from a first source and a second volute for receiving gas from a second source; the first and second volutes being separated by a dividing wall; and an inlet passageway surrounding the wheel and fluidly connected to the volutes; the inlet passageway at least partially defined between a first wall and an opposite second wall, the first wall being moveable along the axis to vary the size of the inlet passageway; wherein a tip of the dividing wall defines a first radius relative to the axis, and a radially outermost part of the first wall positioned within the inlet passageway defines a second radius relative to the axis, and wherein the first radius is at least around 1% larger than the second radius.