Inlet Nozzle Rib Structure for Turbomachine Gap Flow Control
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Solution Overview
Problem
Inlet nozzle assemblies and turbomachines suffer from axial and radial gaps between the inner surfaces of the inlet nozzle assembly and the impeller or its cover plate, leading to a division of the flow into usable and unusable secondary flows, which deteriorates pressure and volume flow curves and acoustic behavior.
Innovation Solution
The inlet nozzle assembly features radial and axial ribs that extend into the gaps between the impeller and its cover plate, minimizing the radial and axial gaps without contact, and are designed to direct the flow effectively to the inflow side, reducing secondary flows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the inlet nozzle assembly is positioned close to the impeller to minimize gaps, then secondary flow is reduced and performance is improved, but the risk of contact between the inlet nozzle assembly and the rotating impeller increases
Solution Approach 1:
The inlet nozzle assembly is designed with adjustable positioning capability, allowing it to be dynamically positioned at optimal distances from the impeller. This enables the system to adapt the gap size between the inlet nozzle assembly and impeller, minimizing secondary flow while preventing contact during operation
Solution Approach 2:
The system allows for changing the positional parameters of the inlet nozzle assembly relative to the impeller. By adjusting the distance and alignment parameters, the design optimizes the balance between minimizing gaps (to reduce secondary flow) and maintaining safe clearance (to prevent contact)
2Productivity
If radial and axial ribs are added to minimize gaps, then secondary flow is reduced and performance is improved, but device complexity increases
Solution Approach 1:
The inlet nozzle assembly is segmented into functional components including radial ribs and axial ribs that can be independently designed and positioned. This segmentation allows each rib structure to specifically address gap reduction in its respective direction (radial or axial) without requiring a complete redesign of the entire assembly
Solution Approach 2:
Radial ribs and axial ribs are added only in specific locations where gap reduction is most needed, rather than uniformly throughout the entire inlet nozzle assembly. This localized approach minimizes secondary flow in critical areas while keeping the overall structural complexity manageable
Data Source
AI summary
An inlet nozzle assembly for the suction-side arrangement on an impeller rotatable about a rotational axis, having a front end section and an adjoining casing section. The casing section has a wall surrounding the rotational axis which forms a receiving space for receiving the impeller, so that a radial gap is formed in the radial direction between the circumferential wall and a radially outer end section of the impeller, and the end section has a front wall with an inlet nozzle which extends into the receiving space. In the end section between the front wall and a front side of the impeller an axial gap is formed, wherein radial ribs extend from the circumferential wall into the receiving space to reduce the radial gap, and/or that axial ribs extend from the end wall to the receiving space to reduce the axial gap.