Centrifugal Compressor Diaphragm Internal Cooling Pathway

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Solution Overview

Problem

Multistage compressors face increased work input due to elevated gas temperatures, leading to inefficiencies and the need for complex and costly interstage coolers to manage thermal energy.

Innovation Solution

An internally-cooled centrifugal compressor design featuring a diaphragm with a gas side and coolant side, where a cooling pathway maximizes heat transfer through a counter-flow configuration, reducing the requirement for external coolers and enhancing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If interstage coolers with external heat exchangers are used to cool compressed gas, then gas temperature is reduced, but system size and complexity increase

Engineering Contradiction:
Improvegas temperatureVSAvoidsystem complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The cooling function is merged with the diaphragm structure itself. The diaphragm incorporates internal coolant passages that allow cooling fluid to flow through the walls separating gas flow paths, integrating the heat exchanger function directly into the structural component rather than using separate external equipment.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The coolant passages are nested within the diaphragm walls. The cooling channels are embedded inside the diaphragm structure, allowing the cooling system to be contained within the existing component geometry without adding external bulk or complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Temperature

If interstage coolers with external heat exchangers are used to cool compressed gas, then gas temperature is reduced, but system size increases

Engineering Contradiction:
Improvegas temperatureVSAvoidsystem size
Core Design Contradiction:
TemperatureVSVolume of stationary object

Solution Approach 1:

The cooling function is merged with the diaphragm structure itself. The diaphragm incorporates internal coolant passages that allow cooling fluid to flow through the walls separating gas flow paths, integrating the heat exchanger function directly into the structural component rather than using separate external equipment.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cooling passages utilize the wall thickness dimension of the diaphragm. By embedding channels within the diaphragm walls rather than adding external cooling equipment, the solution exploits the existing three-dimensional space of the component structure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Temperature

If interstage coolers with additional equipment are used to cool compressed gas, then gas temperature is reduced, but maintenance requirements and costs increase

Engineering Contradiction:
Improvegas temperatureVSAvoidmaintenance requirements
Core Design Contradiction:
TemperatureVSEase of repair

Solution Approach 1:

The cooling function is merged with the diaphragm structure itself. The diaphragm incorporates internal coolant passages that allow cooling fluid to flow through the walls separating gas flow paths, integrating the heat exchanger function directly into the structural component rather than using separate external equipment.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The diaphragm structure performs dual functions: structural separation of gas paths and thermal management. By combining these functions, the system eliminates the need for separate maintenance of external cooling equipment, as the cooling capability is inherent to the diaphragm itself.

Inventive Principle:
Principle #25Self-service

4Device complexity

If traditional compression without internal cooling is used, then system complexity is reduced, but work input per unit pressure increase rises

Engineering Contradiction:
Improvesystem complexityVSAvoidwork input
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The cooling function is merged with the diaphragm structure itself. The diaphragm incorporates internal coolant passages that allow cooling fluid to flow through the walls separating gas flow paths, integrating the heat exchanger function directly into the structural component rather than using separate external equipment.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The heat generated by compression, which is normally a harmful effect increasing work requirements, is converted into a manageable thermal load that can be efficiently removed through the internal coolant passages. The compression process itself provides the temperature differential needed to drive heat transfer to the coolant.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 internally-cooled compressor effectively transfers heat from compressed gas, reducing the work input required per unit pressure increase, thereby improving energy efficiency and reducing system complexity and maintenance costs.

Implementation Method 1

heat from a gas flowing through the gas side is extracted via the coolant side

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

cooling water passage in a disc-like hollow diffused for guiding the gas in the radial direction outward from its outer peripheral part

Methodology Applied
Scientific EffectCounter-flow heat exchange: Heat Exchanger

Data Source

PatentEP2961990B1Method of construction for internally cooled diaphragms for centrifugal compressor
Publication Date: 2020.04.22 DRESSER RAND CO
  • EP2961990B1 patent drawingFigure 1
  • EP2961990B1 patent drawingFigure 2
  • EP2961990B1 patent drawingFigure 3

AI summary

An internally-cooled compressor is provided including a casing and a diaphragm disposed in the casing. The diaphragm includes a diaphragm box defining a plurality of box channels and a bulb defining a plurality of bulb channels. A plurality of return channel vanes connect the diaphragm box and bulb in fluid communication, such that each return channel vane defines a plurality of return vane conduits coupled in fluid communication with the plurality of box channels and the plurality of bulb channels thereby forming a section of a cooling pathway. The cooling pathway is configured such that a cooling agent introduced from an external coolant source into the diaphragm box and flowing through a box channel flows through a return vane conduit into and through a bulb channel and back through another return vane conduit into another box channel before flowing back to the external coolant source.