Centrifugal Compressor Inlet Flow Segmentation for Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Centrifugal compressors face limitations in achieving a broad performance range due to the opposing demands of high exhaust gas recirculation for low-emissions strategies, which increase compressor pressure ratio and reduce mass flow rate, making it challenging to maintain efficiency and stability across varying operating conditions.
Innovation Solution
The implementation of a centrifugal turbomachine with a performance-range-enhancing treatment that includes injecting high-momentum flow into the blade-tip-clearance gap, using non-self-bleed techniques such as Coanda-style or angled-slot injectors, and modulating inlet flow between primary and secondary regions to optimize compressor performance across different flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If high exhaust gas recirculation is used to reduce emissions, then emissions control is improved, but compressor mass flow rate is reduced and pressure ratio increases, driving the compressor towards unstable operating limits
Solution Approach 1:
The compressor inlet flow is segmented into two separate paths: a primary flow path that handles the majority of the mass flow, and a secondary flow path that handles a portion of the flow. This segmentation allows the compressor to operate stably across a broader range of conditions by distributing the flow through different pathways, preventing the compressor from being driven to unstable operating limits during high EGR conditions.
Solution Approach 2:
The system dynamically switches between primary and secondary flow paths based on operating conditions. During high EGR conditions, the secondary flow path is activated to maintain stable compressor operation, while during normal conditions, the primary flow path handles the flow. This dynamic adaptation allows the compressor to maintain reliability across varying emissions control requirements.
2Productivity
If the compressor is designed for high flow rates to meet rated power conditions, then productivity is improved, but efficiency is reduced during low-flow high EGR conditions
Solution Approach 1:
Different regions of the compressor inlet are provided with different flow path characteristics. The primary flow path is optimized for high-flow conditions with appropriate geometry and flow angles, while the secondary flow path is optimized for low-flow conditions. This local differentiation allows each flow path to operate at its optimal efficiency point for its intended flow regime, preventing energy losses that would occur if a single design had to compromise for both conditions.
3Device complexity
If a single compressor is used to cover the broad operating range, then device complexity is reduced, but performance across the full range is compromised
Solution Approach 1:
The compressor inlet is designed with multi-functionality by incorporating both primary and secondary flow paths within a single compressor housing. This universal design allows the same compressor to handle both high-flow rated power conditions and low-flow high EGR conditions effectively, eliminating the need for separate compressors while maintaining performance across the full operating range.
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 approach extends the stable operating range and performance of centrifugal compressors, enhancing efficiency and stability without causing significant losses, allowing for improved engine performance and emissions control across a wider range of conditions.
Implementation Method 1
injecting a high-momentum flow so as to reenergize flow within the blade-tip-clearance gap
Implementation Method 2
using non-self-bleed techniques such as Coanda-style or angled-slot injectors
Data Source
AI summary
Centrifugal turbomachines, such a centrifugal compressors, centrifugal blower, and centrifugal pumps, having unique treatments that enhance their performance ranges. In one arrangement, the treatment involves injecting a relatively high-momentum flow proximate to the blade-tip clearance gap at the inlet to the impeller of the turbomachine in a manner that reenergizes flow at the gap. The injected high-momentum flow can be taken from a location downstream of the outlet of the impeller and/or from a flow external to the turbomachine. In another arrangement, the non-self-bleed-type treatment involves providing the centrifugal turbomachine with a secondary flow path upstream of the inlet to the impeller. In one example, the flow of working fluid to the secondary flow path is modulated according to the mass flow of the working fluid. During times of higher flow, the secondary flow path is opened, and at times of lower flow, the secondary flow path is closed.