Variable Capacity Turbine Inlet Flow Path Design

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Solution Overview

Problem

Variable capacity turbines experience reduced performance and flow rate due to separation from the outer peripheral face of the involute dividing wall at the inlet portion of the outer scroll, leading to decreased flow velocity and efficiency.

Innovation Solution

A variable capacity turbine design featuring a continuous and gentle throttle flow path at the inlet portion of the outer scroll, with a flow regulating valve that maintains a constant turning angle and parallel alignment of the flow control valve with the central axis, reducing separation and enhancing flow acceleration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the flow path sectional area at the inlet portion of the outer scroll increases from upstream to downstream, then the flow path becomes easier for exhaust gas passage, but the flow velocity decreases and separation occurs from the outer peripheral face of the involute dividing wall

Engineering Contradiction:

Improveflow path designVSAvoidflow velocity

Core Design Contradiction:

Ease of manufactureVSSpeed

Solution Approach 1:

Instead of increasing the flow path sectional area from upstream to downstream as in conventional designs, the patent inverts this approach by designing the flow path so that the sectional area gradually decreases or remains controlled in a specific pattern. This inversion prevents flow velocity reduction and eliminates separation from the outer peripheral face of the involute dividing wall, thereby resolving the technical contradiction.

Inventive Principle:

Principle #13The other way round (Inversion)

2Productivity

If the flow path sectional area at the inlet portion of the outer scroll increases from upstream to downstream, then the flow path is more open, but separation from the outer peripheral face of the involute dividing wall occurs reducing performance

Engineering Contradiction:

Improveflow rateVSAvoidperformance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies the inversion principle by reversing the conventional flow path area increase design. Instead of allowing the flow path sectional area to increase from upstream to downstream, the design controls or decreases the area in a specific pattern, which prevents flow separation and maintains high performance while still achieving adequate flow rate.

Inventive Principle:

Principle #13The other way round (Inversion)

3Productivity

If the flow control valve is positioned to fully open the introducing port, then the flow rate increases, but the turning angle of fluid increases causing separation

Engineering Contradiction:

Improveflow rateVSAvoidseparation loss

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by optimizing the geometric parameters of the flow control valve and its positioning. Specifically, the valve is designed with a flat face that aligns parallel to the central axis of the inlet flange when fully open, and the flow path is designed with controlled sectional area variation. These parameter changes reduce the fluid turning angle even when the port is fully open, thereby preventing separation loss while maintaining high flow rate.

Inventive Principle:

Principle #35Parameter changes

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

The design suppresses separation from the outer peripheral face of the involute dividing wall, thereby enhancing performance and increasing the flow rate, resulting in improved efficiency and reduced losses.

Implementation Method 1

the flow path sectional area gradually reduces, which facilitates acceleration of the exhaust gas at the inlet portion of the outer scroll

Methodology Applied

Scientific EffectFlow acceleration through gradual area reduction: Venturi Effect

Implementation Method 2

suppresses separation from the outer peripheral face of the upstream tip end portion of the involute dividing wall

Methodology Applied

Scientific EffectFlow separation suppression: Flow Separation

Data Source

PatentUS8814506B2Variable capacity turbine

Publication Date: 2014.08.26 MITSUBISHI HEAVY IND ENGINE & TURBOCHARGER LTD

AI summary

There is provided a variable capacity turbine that is capable of suppressing separation from an outer peripheral face of an involute dividing wall at an inlet portion of an outer scroll, enhancing performance, and increasing a flow rate. The variable capacity turbine includes: a turbine housing having an involuted scroll formed therein; a turbine wheel rotatably provided on an inner periphery side of the scroll; the involute dividing wall mounted on the turbine housing to divide the scroll into an inner scroll and the outer scroll; and a flow regulating valve for opening and closing an introducing port formed at an inlet end of the outer scroll. The inlet portion of the outer scroll is formed to have a continuous and gentle throttle flow path from an upstream side to a downstream side.