Radial Turbo Compressor Inlet With Relaxation Chamber Flow Equalization

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Solution Overview

Problem

Conventional centrifugal turbo-compressors with tangential gas suction inlets suffer from non-homogeneous flow distribution and flow distortions, leading to reduced efficiency and surge limits.

Innovation Solution

The design incorporates a relaxation chamber and angularly distributed inlet flow guide channels that minimize pressure losses and flow distortions by allowing the gas flow to enter radially into the relaxation chamber, ensuring a more homogeneous flow distribution at the impeller inlet.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a tangential gas suction inlet is used in a conventional centrifugal turbo-compressor, then the structure is simple and easy to manufacture, but the flow distribution becomes non-homogeneous and flow distortions occur at the impeller inlet

Engineering Contradiction:
Improveease of manufactureVSAvoidflow distribution uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent introduces an intermediary component called a 'flow conditioner' between the tangential gas suction inlet and the impeller inlet. This flow conditioner includes flow guide vanes that rectify the distorted flow pattern, converting the non-homogeneous flow from the tangential inlet into a more uniform axial flow at the impeller inlet, thereby resolving the contradiction between simple inlet structure and flow uniformity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The flow conditioner is segmented into multiple flow guide vanes angularly distributed around the inlet axis. Each vane handles a portion of the flow, collectively transforming the overall flow pattern. This segmentation allows the system to process the complex tangential flow in manageable sections, achieving uniform flow distribution while maintaining manufacturing simplicity

Inventive Principle:
Principle #1Segmentation

2Device complexity

If a tangential gas suction inlet is used, then the device structure remains simple, but compressor efficiency and surge limit are strongly impacted

Engineering Contradiction:
Improvedevice complexityVSAvoidcompressor efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The flow conditioner acts as an intermediary device that minimally increases structural complexity while dramatically improving compressor efficiency. By placing this relatively simple component in the flow path, the patent achieves homogeneous flow distribution at the impeller inlet, which directly enhances compressor performance and surge margin without requiring complete redesign of the inlet structure

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If flow guide channels are added to correct flow distribution, then flow homogeneity improves, but device complexity increases

Engineering Contradiction:
Improveflow distribution uniformityVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The flow guide vanes are designed with specific angular orientations and curved profiles that dynamically adapt to the incoming tangential flow pattern. The vanes are angled to gradually redirect the flow from tangential to axial direction, creating a dynamic flow transformation that achieves uniform distribution without requiring complex multi-component assemblies

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The flow conditioner is merged with the existing inlet distributor structure, combining the flow rectification function with the existing flow distribution geometry. This integration allows the patent to achieve flow homogenization without adding completely separate complex components, thereby improving flow uniformity while limiting the increase in device complexity

Inventive Principle:
Principle #5Merging (Combining)

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 enhances compressor efficiency while facilitating easy manufacturing and reducing flow distortions, resulting in improved operational performance.

Implementation Method 1

the gas flow, coming out of the gas suction inlet, flows through the relaxation chamber at low speed, which substantially minimizes the pressure losses at the inlet of the gas flow path and substantially minimizes the flow distortions through the inlet flow guide channels

Methodology Applied
Scientific EffectPressure equalization: Pressure Gradient

Data Source

PatentEP3647598B1Radial inlet for turbo compressor
Publication Date: 2026.04.22 DANFOSS AS
  • EP3647598B1 patent drawingFigure 1~2
  • EP3647598B1 patent drawingFigure 3~4
  • EP3647598B1 patent drawingFigure 5~7

AI summary

The centrifugal turbo-compressor (2) includes a hermetic casing (3); a drive shaft (6) having a longitudinal axis and rotatably arranged within the hermetic casing (3); a compression stage including an impeller (17) connected to the drive shaft (6); a gas suction inlet (42); and a gas flow path (P) fluidly connected to the gas suction inlet (42) and configured to supply the compression stage with a gas flow. The gas flow path (P) includes a relaxation chamber (46) at least partially surrounding the drive shaft (6), the gas suction inlet (42) emerging substantially radially into the relaxation chamber (46); and a plurality of inlet flow guide channels (51) fluidly connected to the relaxation chamber (46) and angularly distributed around the longitudinal axis of the drive shaft (6), the inlet flow guide channels (51) extending radially towards the drive shaft (6) and being axially offset from the gas suction inlet (42) and the relaxation chamber (46).