Stiffened Turbo Pump Casing Curved Wall Stress Distribution

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Solution Overview

Problem

Turbomachine casings under high fluid pressures face deformation and mechanical stress issues, leading to potential leakage and structural integrity problems due to flange rotation and high material costs from complex manufacturing techniques.

Innovation Solution

A turbomachine casing design featuring an annularly curved wall portion and an outer annular web that distributes deformations axially and radially, reducing flange pivoting and stress levels, and allowing for simpler manufacturing methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If axial ribs are provided to stiffen the casing, then the casing rigidity is improved, but the manufacturing complexity and cost increase

Engineering Contradiction:
Improvecasing rigidityVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent replaces conventional axial ribs with a curved annular reinforcement element that follows the circumferential direction. This curved structure provides the necessary stiffening effect through its geometric configuration, eliminating the need for complex ribbed structures while maintaining casing rigidity under high pressure conditions.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Stability of the object's composition

If conventional stiffening ribs are used, then casing deformation is limited, but flange pivoting and leakage risks increase

Engineering Contradiction:
Improvecasing deformation controlVSAvoidsealing reliability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The curved annular reinforcement element distributes stress more uniformly around the casing perimeter, preventing localized deformations that would cause flange pivoting. The continuous curved geometry provides uniform support along the sealing interface, maintaining flange alignment and preventing yawning openings that lead to leakage.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention changes the geometric parameters of the reinforcement structure from linear axial ribs to a curved circumferential element. This parameter change alters the stress distribution pattern, transforming concentrated stresses at rib locations into distributed stresses along the curved path, thereby improving sealing reliability.

Inventive Principle:
Principle #35Parameter changes

3Strength

If high-strength materials are selected to reduce stress, then structural integrity is improved, but manufacturing cost increases

Engineering Contradiction:
Improvestress resistanceVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The curved reinforcement geometry optimizes the structural efficiency of the material used. By following the natural stress flow paths in the casing wall, the curved element achieves maximum stiffening effect with minimum material, allowing the use of standard materials rather than expensive high-strength alloys while maintaining structural integrity.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP2375006B1Stiffened turbo pump casing
Publication Date: 2015.09.23 SN DETUDE & DE CONSTR DE MOTEURS DAVIATION (S N E C M A)
  • EP2375006B1 patent drawingFigure 1~2

AI summary

The casing has two parts with different diameters, where the part with large diameter is provided with a mounting flange (16). A portion (25) of an annular wall extends between the mounting flange and the part with smaller diameter (23) with an annular curved form with its convexity directed toward interior of the casing. An annular web (29) extends in parallel and at distance from the portion of the wall between the flange and the part with smaller diameter. The web comprises multiple openings (34) that are regularly and circumferentially arranged.