Compressor Discharge Nozzle Pressure Loss for Low-Flow Stability
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Solution Overview
Problem
Centrifugal compressors exhibit unstable operation at low flow rates due to insufficient pressure loss on the discharge nozzle side, which affects the lifting height and stability, as existing area adjusting means fail to achieve uniform pressure loss distribution in the complex outlet scroll.
Innovation Solution
A pressure loss body with a plate shape, potentially perforated, is strategically placed at the radially outer end or center of the discharge nozzle, allowing for adjustable pressure loss by blocking part of the flow path cross-section, ensuring uniform flow distribution and easy adjustment of pressure loss magnitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If area adjusting means is provided in the outlet scroll to reduce flow path sectional area, then pressure loss can be increased at low flow rates, but the flow distribution remains non-uniform due to the complicated shape of the outlet scroll
Solution Approach 1:
The invention extracts the area adjusting means from the outlet scroll and relocates it to the discharge nozzle. This separation allows the pressure loss adjustment function to be independent from the complex scroll geometry, enabling uniform flow distribution while maintaining the desired pressure loss characteristics at low flow rates
Solution Approach 2:
The invention applies local quality by positioning the area adjusting means specifically at the radially outer end of the discharge nozzle where the flow path cross-section has more uniform flow distribution. This localized placement optimizes the pressure loss adjustment effect while ensuring uniform flow characteristics
2Loss of energy
If area adjusting means is provided in the outlet scroll, then pressure loss can be incurred, but the complicated shape makes it difficult to achieve desired pressure loss magnitude
Solution Approach 1:
The area adjusting means is extracted from the complicated outlet scroll structure and relocated to the simpler discharge nozzle. This relocation enables more precise control over pressure loss magnitude because the discharge nozzle has a more regular geometry that is easier to manufacture and adjust with high precision
Solution Approach 2:
The invention enables parameter changes by providing an adjustable area adjusting means in the discharge nozzle that can modify the flow path cross-sectional area. This allows the pressure loss magnitude to be tuned and optimized for different operating conditions, particularly for low flow rate stability
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 ensures stable operation at low flow rates by effectively adjusting pressure loss, enhancing accessibility and precision in pressure loss adjustment, and simplifying the adjustment process at a lower cost.
Implementation Method 1
pressure loss of a working fluid in the discharge nozzle can be ensured
Implementation Method 2
a discharge scroll that is provided at an end of the flow path on a downstream side and extends in a spiral shape around the main axis
Implementation Method 3
a discharge nozzle that communicates with the discharge scroll on the downstream side and extends from the discharge scroll in a tangent direction around the main axis
Data Source
AI summary
A compressor includes a rotation shaft that is capable of rotating around a main axis, an impeller provided integrally with the rotation shaft, a casing that covers the impeller from an outer circumferential side and forms a flow path through which a working fluid circulates, a discharge scroll that is provided at an end of the flow path on a downstream side and extends in a spiral shape around the main axis, a discharge nozzle that communicates with the discharge scroll on the downstream side and extends from the discharge scroll in a tangent direction around the main axis, and a pressure loss body that has a plate shape extending in a direction orthogonal to an axis of the discharge nozzle extending in a radial direction orthogonal to the main axis and is capable of blocking a part of a flow path cross-section of the discharge nozzle.