Ultrasonic Flow Meter with Oppositely Twisted Mixing Means
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ultrasonic flow meters face inaccuracies in flow rate measurements due to flow disturbances such as irregular fluctuations and swirls, leading to non-linearity and non-repeatability in measurements.
Innovation Solution
An ultrasonic flow meter with a flow mixer comprising at least a first and second oppositely twisted mixing means placed upstream of the measuring section, which counteracts swirls by having a larger impeding effect on clockwise than counter-clockwise rotations, thereby reducing flow disturbances and improving measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If flow straighteners are introduced in the flow passage to reduce flow disturbances, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The flow mixer is divided into multiple mixing elements (first and second mixing means) that are oppositely twisted, each segment contributing to the overall flow conditioning function. This segmentation allows the complex task of flow straightening to be distributed across multiple simpler components.
Solution Approach 2:
The mixing elements are designed with asymmetric twisting directions (opposite helical directions) to create complementary flow disturbances that collectively eliminate swirls and irregular fluctuations. The asymmetric design allows each element to target specific flow distortion patterns.
2Reliability
If flow disturbances are reduced by introducing flow straighteners, then measurement repeatability is improved, but pressure drop increases
Solution Approach 1:
The mixing elements intentionally create controlled flow disturbances (swirling motion) that paradoxically eliminate harmful swirls and irregular fluctuations downstream. The beneficial effect is achieved by first introducing controlled chaos that then self-organizes into a more uniform flow pattern.
Solution Approach 2:
The oppositely twisted mixing elements create periodic flow disturbances that alternate in direction, effectively canceling out cumulative swirl effects. This periodic action ensures that flow disturbances are continuously corrected as fluid passes through the mixing section.
3Stability of the object's composition
If mixing means are added to counteract swirls, then flow profile symmetry is improved, but manufacturing complexity increases
Solution Approach 1:
The mixing elements serve multiple functions simultaneously: they create swirling motion for mixing, generate complementary flow disturbances for flow conditioning, and act as flow straighteners. This multi-functionality reduces the need for separate components for each function.
Solution Approach 2:
Instead of trying to directly straighten flow with conventional vanes, the invention uses oppositely twisted elements that create reverse swirling effects. This inverted approach of using controlled swirl to eliminate swirl simplifies the geometric design compared to traditional straightener configurations.
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 flow mixer effectively reduces swirls and other flow disturbances, resulting in more consistent and accurate flow measurements with a minimal pressure drop, enhancing the overall performance of the ultrasonic flow meter.
Implementation Method 1
The mixing device comprises at least two tabs inclined in the flow direction. The length and width of the tabs are selected so as to generate pairs of oppositely rotating predominantly streamwise vortices at the tips of each tab. The mixing device generates a controlled generation of vortices, or swirling motion in the flow
Implementation Method 2
The mixing device generates a controlled generation of vortices, or swirling motion in the flow, such that the swirling motion cause the movement of fluid perpendicular to the main flow direction with the effect of producing adequate cross-stream mixing
Implementation Method 3
an ultrasonic flow meter typically comprises a flow passage embracing a measuring section wherein ultrasonic signals are propagating along the flow direction and in the opposite direction, so that the propagation speeds can be compared for the two directions
Implementation Method 4
ultrasonic signals are propagating along the flow direction and in the opposite direction, so that the propagation speeds can be compared for the two directions, and from the comparison extracting the flow rate
Data Source
Figure 1A~5C
Figure 2A~2B
Figure 3A~3B
AI summary
The invention relates to an ultrasonic flow meter comprising a flow passage, an ultrasound transducer and a flow straightener for removing or diminishing flow disturbances such as swirls. The flow straightener comprises at least a first and a second straightening means being oppositely twisted along a flow direction with a given twisting angle. The measurement accuracy of a flow meter is improved by the presence of the flow straightener.