Internal Force Transducer Balance for Aerodynamic Interference
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Solution Overview
Problem
Current wind-tunnel balances are unable to accurately measure aerodynamic interference forces, such as those encountered during powered descent, due to limitations in their design, which restricts the measurement of axial forces and introduces parasitic load paths, affecting measurement accuracy.
Innovation Solution
An internal force transducer balance system with an axial strain measurement component and an integral fluid flow path that extends through the balance body, allowing for direct measurement of aerodynamic interference forces and moments, while maintaining measurement accuracy by eliminating parasitic load paths through a continuous flow-through design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an internal balance structure is used to measure aerodynamic loads, then measurement capability is improved, but the ability to measure aerodynamic interference forces deteriorates due to parasitic load paths
Solution Approach 1:
The balance body is divided into multiple measurement components (lateral strain measurement component, axial strain measurement component, and moment measurement component) that are spatially segmented and functionally independent. This segmentation allows each component to measure specific force components without interference from parasitic load paths, enabling both traditional aerodynamic load measurement and new aerodynamic interference force measurement capabilities.
Solution Approach 2:
The axial strain measurement component is extracted as a separate functional element within the balance body, specifically designed to measure axial forces (such as powered descent forces) independently from other measurement functions. This extraction eliminates the parasitic load path problem that previously prevented accurate measurement of aerodynamic interference forces.
2Stress or pressure
If fluid flow paths are routed through the balance body, then high-pressure application capability is improved, but measurement accuracy deteriorates due to parasitic load paths
Solution Approach 1:
The balance body is designed with differentiated local properties: the lateral strain measurement component and moment measurement component are positioned and structured to be substantially isolated from fluid flow paths, while the axial strain measurement component is specifically designed to accommodate fluid flow. This local quality differentiation allows fluid flow paths to pass through the balance body for high-pressure applications without creating parasitic load paths that would affect measurement accuracy.
3Measurement precision
If the balance body structure is simplified for direct force measurement, then measurement capability is improved, but structural integrity deteriorates
Solution Approach 1:
The balance body employs an asymmetric structural design where the lateral strain measurement component and moment measurement component are positioned and dimensioned differently from the axial strain measurement component. This asymmetric design allows each component to be optimized for its specific measurement function while collectively maintaining the overall structural integrity of the balance body.
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
Enables precise measurement of aerodynamic interference forces and moments, improving the accuracy and efficiency of wind-tunnel testing by allowing fluid flow through the structural components, reducing the need for redundant tests and enhancing the capability to handle high-pressure applications.
Implementation Method 1
an axial strain measurement component of the balance body, wherein the axial strain measurement component is configured to measure an axial force applied to the internal balance
Data Source
AI summary
There is a need to develop new internal balance structures that allow for measurements of aerodynamic interference forces (e.g., powered descent forces) in addition to aerodynamic loads. For example, supersonic retropropulsion (SRP) is a technique involving thrusters in opposition to the oncoming airflow to decelerate an aircraft vehicle while traveling at supersonic speeds. SRP has been identified as a key entry, descent, and landing technology for future Mars missions and for reuse of rocket boosters on Earth. Because of the propellant and oxidizer mass required for the thrusters, currently proposed SRP configurations require a significant increase in performance and efficiency before considered an effective solution. The challenge is that this procedure may cause the air around the spacecraft to become unstable. Accordingly, the present disclosure describes systems and methods for measuring aerodynamic interference forces in addition to aerodynamic loads using an improved internal force balance or integral flow-through force transducer.