Centrifugal Compressor Impeller Eye Cooling via Segmented Ports
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Solution Overview
Problem
Centrifugal compressors face reduced creep life due to high temperatures, especially in the impeller eye region, where existing materials and cooling techniques fail to maintain the required 60,000-hour creep life, and traditional materials perform inadequately.
Innovation Solution
A centrifugal compressor design incorporating a shrouded impeller with a cooling medium delivered at the impeller eye through strategically arranged ports and holes, utilizing a portion of the working medium to efficiently cool the impeller eye and surrounding areas, thereby maintaining the creep life and reducing temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If traditional materials and cooling techniques are used in the impeller eye region, then the compressor can operate, but the creep life requirement of 60,000 hours cannot be met due to high temperatures
Solution Approach 1:
The impeller eye region is segmented into multiple cooling zones with strategically positioned cooling ports and internal holes, allowing localized temperature control in different areas of the impeller eye to achieve uniform cooling and extend creep life
Solution Approach 2:
A cooling medium is introduced as an intermediary substance between the hot impeller eye region and the external environment. The cooling medium absorbs heat through convection and conduction, transporting it away from the impeller eye to maintain temperatures below critical thresholds for 60,000-hour creep life
2Duration of action of stationary object
If nickel-based super alloys like Inconel 738 are used to meet creep life requirements, then the creep life requirement is satisfied, but manufacturability and reparability become critical issues
Solution Approach 1:
Instead of changing the material composition to nickel-based super alloys, the invention changes the thermal parameters by introducing active cooling. This allows the use of more manufacturable materials while achieving the required 60,000-hour creep life through temperature control rather than material substitution
3Temperature
If cooling medium ports are strategically arranged around the impeller eye, then cooling efficiency is improved, but device complexity increases
Solution Approach 1:
The cooling medium serves multiple functions simultaneously: it cools the impeller eye region, removes heat through convection, and can be part of the overall compressor working fluid system. This multi-functionality reduces the need for separate cooling systems and minimizes overall device complexity while maintaining high cooling efficiency
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 cooling mechanism effectively reduces the temperature of the impeller eye and surrounding areas, enhancing the creep life of the impeller and improving the overall performance of the compressor by using the working medium itself for cooling, eliminating the need for separate pumping means and maintaining the composition of the working medium.
Implementation Method 1
a cooling medium is delivered at the impeller eye, to remove heat from this area of the impeller
Implementation Method 2
The cooling medium delivered in the region of the impeller eye locally removes heat and keeps the temperature of the impeller eye and of the surrounding area under a critical value
Data Source
Figure 1
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AI summary
A centrifugal compressor is disclosed, comprising: a casing (41); at least one impeller (21) supported for rotation in the casing and provided with a hub (23), a shroud (25) and an impeller eye (31); an impeller-eye sealing arrangement (39), for sealing the impeller in the region of said impeller eye. The centrifugal compressor further comprises at least one cooling-medium port (53) located at the impeller-eye sealing arrangement, arranged for delivering a cooling medium around the impeller eye.