Centrifugal Compressor Flow Control Blades with Bleed Gaps
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Solution Overview
Problem
Centrifugal compressors have narrow operating ranges, particularly at lower mass flows, leading to inefficiencies and potential blockages, with existing designs failing to effectively improve flow conditions in such scenarios.
Innovation Solution
The design incorporates flow-control blades with inducer and main sections that form bleed gaps, featuring different lean angles and camber line distributions, allowing fluid to flow from pressure sides to suction sides, thereby enhancing efficiency at lower mass flows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a tandem inducer is added to the impeller to reduce shock losses, then efficiency at lower mass flows is improved, but device complexity increases due to additional discrete inducer blades and gaps
Solution Approach 1:
The patent merges the inducer and main blade sections into a single integrated flow control blade structure. The inducer section is formed as a continuous extension of the main blade section, eliminating the need for discrete inducer blades and the gaps between them. This integration maintains the shock loss reduction benefits while simplifying the overall blade structure.
Solution Approach 2:
The flow control blade is segmented into an inducer section and a main blade section, with the inducer section positioned upstream. This segmentation allows the inducer portion to specifically address shock losses at lower mass flows while the main blade section handles the primary compression function, resolving the contradiction by providing specialized functionality without requiring separate discrete components.
2Adaptability or versatility
If the operating range is increased to accommodate lower mass flows, then versatility is improved, but efficiency deteriorates due to blockages along the shroud
Solution Approach 1:
The patent applies local quality by providing different blade geometries at different radial positions. The inducer section has specific lean angles and camber line distributions optimized for lower mass flow conditions, while the main blade section maintains geometry optimized for design point operation. This localized optimization allows the compressor to maintain efficiency across a broader operating range.
Solution Approach 2:
The patent changes geometric parameters of the flow control blades, specifically the lean angles and camber line distributions, to optimize performance at lower mass flows. By adjusting these parameters in the inducer section while maintaining the main blade section geometry, the compressor achieves improved versatility without sacrificing 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
This configuration improves the efficiency of centrifugal compressors at mass flows below the design point by reducing shock losses and expanding the operating range, particularly at lower mass flows, compared to conventional designs without bleed gaps.
Implementation Method 1
The bleed gaps are shaped to permit fluid to flow therethrough from the pressure sides to the suction sides
Implementation Method 2
A centrifugal compressor includes an impeller that rotates about an axis. Blades are distributed circumferentially around the rotating axis. The blades are shaped such that the incoming fluid exits the impeller in a radial direction into a diffuser of the centrifugal compressor. The impeller imparts energy to the fluid as the fluid flows therethrough.
Data Source
AI summary
Centrifugal compressor having flow-control blades in which each of the flow-control blades has a pressure side and an opposite suction side. Each of the flow-control blades includes a main section and an inducer section that project away from an impeller surface. The inducer section is positioned upstream from the main section. The inducer section includes a trailing edge and the main section includes a leading edge that is spaced apart from the trailing edge. The inducer sections are aligned with the respective main sections as the inducer and main sections project from the impeller surface to a designated point above the impeller surface. Each of the trailing edges of the inducer sections and the respective leading edge of the main section form a bleed gap therebetween after the designated point. The bleed gap is configured to permit fluid to flow therethrough from the pressure side to the suction side.