Bend Pipe Geometry for Inner-Side Separation Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Bend pipes in fluid machines, such as turbines and compressors, experience separation on the inner side due to centrifugal forces, leading to pressure loss and efficiency deterioration, as existing solutions like eccentric joint lines only partially address the issue of outward flow reduction.
Innovation Solution
A bend pipe design with an outer inclined surface and potential back-side eccentric portion, increasing the flow's inclination towards the inner side, combined with a larger cross-sectional area in the bend pipe portion to reduce centrifugal force and prevent separation, along with inner inclined surfaces to manage reverse flows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an eccentric joint line is used to reduce outward flow velocity, then the velocity distribution becomes more uniform, but a thick boundary layer develops on the inner side causing separation
Solution Approach 1:
The patent applies asymmetry by introducing an eccentric portion that offsets the pipe axial center line from the intersection line of orthogonal planes. This asymmetric positioning creates a deliberate imbalance in the flow path geometry, generating a compensating inward flow component that counteracts the outward centrifugal drift. The eccentric offset distance is specifically designed to create the required asymmetric flow distribution that prevents boundary layer thickening and separation on the inner side.
Solution Approach 2:
The patent changes the geometric parameter of the pipe configuration by introducing an eccentric portion with a specific offset distance. This parameter change modifies the flow field characteristics, transforming the velocity distribution and boundary layer development. The offset distance is optimized to achieve the desired balance between reducing outward flow velocity and preventing inner side separation.
2Ease of manufacture
If the bend pipe portion has a standard circular cross-section, then the manufacturing is simple, but separation occurs on the inner side due to centrifugal force
Solution Approach 1:
The patent modifies the symmetric circular cross-section by introducing an eccentric portion that creates an asymmetric flow path. This asymmetric geometry redistributes the centrifugal force effects, directing flow away from the inner wall and preventing separation. The asymmetric design maintains manufacturing feasibility while effectively mitigating the harmful centrifugal force effects.
Solution Approach 2:
The patent applies local quality by creating a specific asymmetric region (the eccentric portion) within the bend pipe that addresses the local problem of inner wall separation. This localized geometric modification targets the specific area where separation occurs, altering the flow characteristics in that region without requiring complete redesign of the entire pipe structure.
3Reliability
If the pipe axial center line is offset from the intersection line, then separation is suppressed by creating inward flow inclination, but the device complexity increases
Solution Approach 1:
The patent uses asymmetry as a straightforward geometric solution - offsetting the pipe axial center line from the intersection line by a simple distance. This creates the necessary inward flow inclination to suppress separation while adding minimal complexity to the overall device. The asymmetric offset is a single geometric parameter that can be easily incorporated into existing pipe designs.
Solution Approach 2:
The patent changes a single key parameter - the offset distance between the pipe axial center line and the intersection line. This parameter change produces the desired flow control effect (separation suppression) with minimal impact on device complexity. The offset distance can be optimized independently without requiring complex multi-parameter adjustments.
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
Effectively suppresses separation on the inner side of the bend pipe, reducing pressure loss and improving the efficiency of fluid machines by guiding the flow inward and reducing centrifugal deflection.
Implementation Method 1
as a fluid flows through a bend pipe, the fluid may drift outward in the bend direction (outward with respect to the curvature radius) due to a centrifugal force
Implementation Method 2
the velocity of the outward flow in the bend direction of the bend pipe is reduced, so as to achieve a uniform velocity distribution
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A bend pipe for supplying a fluid to a fluid machine or discharging the fluid from the fluid machine, wherein, provided that: a line including a pipe axial center line of an inlet pipe portion and an extension line thereof is defined as a line L; a line including a pipe axial line of an outlet pipe portion and an extension line thereof is defined as a line M; and a direction parallel to an intersection line formed by a plane orthogonal to the line M and a plane orthogonal to the line M is defined as a direction I, and when, as seen from the direction I, a side of the line M on which the inlet pipe portion exists is defined as a front side and a side of the line M on which the inlet pipe portion does not exist is defined as a back side, a side surface on an outer side with respect to a bend direction of a bend pipe portion includes an outer inclined surface on the back side of the line M, the outer inclined surface being inclined so that a distance from the line M decreases toward a downstream side.