Centrifugal Compressor Diaphragm with Integrated Coolant Passages
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Solution Overview
Problem
Existing internally cooled centrifugal compressors have inefficient cooling arrangements, leading to suboptimal efficiency due to limited heat exchange surface area between the processed gas and coolant.
Innovation Solution
The implementation of a multi-stage coolant passage system with thin, high-velocity coolant passages around inner and outer diaphragm portions, enhancing heat removal through forced convection by creating a high-speed coolant flow in close proximity to the gas-exchange surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional intercoolers are used between compression stages, then heat removal efficiency is improved, but device complexity and footprint increase
Solution Approach 1:
The patent combines the intercooling function with the return-channel structure by integrating coolant passages directly into the return-channel diaphragm. This merging eliminates the need for separate intercooler devices and complex piping systems, reducing device complexity while maintaining heat removal efficiency.
Solution Approach 2:
The return-channel diaphragm serves dual functions: guiding the gas flow from one compression stage to the next and providing coolant passages for heat removal. This multi-functionality eliminates the need for dedicated intercooler components, simplifying the overall system structure.
2Temperature
If coolant passages are made larger to improve heat exchange, then heat removal efficiency improves, but space for gas flow is reduced
Solution Approach 1:
The coolant passages are nested within the return-channel diaphragm structure itself, utilizing the wall thickness and internal space of the diaphragm. This nesting approach provides adequate heat exchange surface area without occupying additional space that would be needed for gas flow.
Solution Approach 2:
The patent utilizes thin-walled return-channel diaphragms with integrated coolant passages. The thin film structure provides sufficient heat exchange area while minimizing the space occupied, leaving adequate room for gas flow through the return channel.
3Temperature
If coolant flow velocity is increased to improve forced convection, then heat removal efficiency improves, but pressure drop increases
Solution Approach 1:
The patent transitions from one-dimensional straight coolant passages to two-dimensional serpentine or multi-pass pathways within the diaphragm. This dimensional change allows the coolant to maintain higher velocities for improved convection while distributing the pressure drop across multiple segments, reducing the overall pressure loss.
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 configuration significantly improves heat removal efficiency by increasing the thermal exchange effectiveness, reducing the power required for gas compression and enhancing the overall performance of the centrifugal compressor.
Implementation Method 1
enhancing heat removal through forced convection by creating a high-speed coolant flow in close proximity to the gas-exchange surfaces
Implementation Method 2
The small sectional dimension of the meatus causes the coolant to move at high velocity in thermal-exchange contact with the inner surface of the peripheral wall formed by the inner diaphragm portion which surrounds the first inner core. The high coolant velocity improves heat removal by convection from the gas which contacts the outer surface of said peripheral wall.
Data Source
AI summary
A compressor comprising: a casing; an upstream impeller and a downstream impeller for rotation in the casing; a diaphragm comprised of an internal portion and an external portion; an upstream diffuser fluidly coupled to an outlet of the upstream impeller; a return channel fluidly coupled to the upstream diffuser and to an inlet of the downstream impeller, the return channel has a plurality of return-channel blades connecting the internal and external diaphragm portions; and a downstream diffuser fluidly coupled to an outlet of the downstream impeller is disclosed. A first coolant passage is in the internal diaphragm portion and extends around an inner core, the first coolant passage being in heat-exchange relationship with the upstream diffuser and the return channel. A second coolant passage and third coolant passage are separated by a second inner core in the external diaphragm portion and in a heat-exchange relationship with the return channel and the downstream diffuser.