Cryogenic Pump Inducer Geometry for Cavitation and Startup Loads
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Solution Overview
Problem
Existing inducers for cryogenic pumps are prone to fracture during startup due to inertial forces, leading to debris and fluid vaporization, which causes cavitation and reduces pump performance, and they struggle with low fluid levels and two-phase fluid handling.
Innovation Solution
The design includes a hub with specific surface sections and blades that extend radially and circumferentially along helical paths with increasing helix angles, along with an inducer guide vane, to manage fluid pressure and flow effectively, preventing cavitation and accommodating low fluid levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing inducers are used in cryogenic pumps, then pump operation is possible, but the inducers are prone to fracture during startup due to inertial forces, leading to debris and pump failure
Solution Approach 1:
The inducer is divided into multiple blade elements arranged radially from the hub, with each blade being a separate structural element. This segmentation allows the inducer to better distribute and handle inertial forces during startup, preventing catastrophic fracture while maintaining operational reliability.
2Reliability
If existing inducers are used, then pump operation is possible, but fluid vaporization occurs in low-pressure conditions, causing cavitation and reduced pump performance
Solution Approach 1:
The inducer blades are designed with specific geometric parameters including helical paths with increasing helix angles, optimized blade angles, and controlled aspect ratios. These parameter changes enable the inducer to maintain fluid pressure above vapor pressure across a wider range of operating conditions, preventing cavitation and vaporization while ensuring stable pump performance.
3Productivity
If existing inducers are used, then pump operation is possible, but they cannot accommodate low fluid levels, reducing effective tank size and productivity
Solution Approach 1:
The inducer design with its hub configuration and radial blade arrangement creates effective suction capability that extends to lower fluid levels. This multi-functional design allows the pump to effectively remove fluid from various液位 conditions, maximizing the usable capacity of storage tanks and improving overall productivity.
4Ease of operation
If existing inducers are used, then pump operation is possible, but inertial forces during startup cause fracture and debris generation
Solution Approach 1:
The inducer blades are designed with root attachments to the hub that provide preliminary structural support and force distribution before full rotational speed is achieved. This preliminary action design ensures that inertial forces during acceleration are distributed evenly, preventing fracture and debris generation while maintaining ease of startup operation.
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
The solution enhances pump performance by maintaining fluid pressure above vapor pressure, reducing cavitation, and enabling efficient handling of low fluid levels and two-phase fluids, increasing productivity and profitability.
Implementation Method 1
The main blades may extend radially from the outer lateral surface of the hub to an outer diameter of the inducer and extend circumferentially along a first helical path over the leading surface section, the intermediate surface section, and the trailing surface section, the first helical path having an increasing helix angle from the leading surface section to the trailing surface section defining a main blade angle.
Implementation Method 2
An inducer's blades may be angled to induce a rotational component to the incoming fluid flow and the inducer may increase the fluid pressure, helping to prevent cavitation by ensuring that the fluid pressure remains above the vapor pressure.
Implementation Method 3
it would be desirable to improve the handling of two-phase fluids (i.e., mixed vapor and liquid fluids)
Data Source
AI summary
An inducer may include a hub having an outer lateral surface extending from a leading end to a trailing end, the outer lateral surface having a leading surface section having a first cylindrical shape, an intermediate surface section having a frustoconical shape, and a trailing surface section having a second cylindrical shape. The inducer may include main blades extending circumferentially along a first helical path over the leading surface section, the intermediate surface section, and the trailing surface section, the first helical path having an increasing helix angle. The inducer may additionally include splitter blades, each of the splitter blades located circumferentially between two of the main blades, respectively.