Internal force transducer balance system for measuring aerodynamic interference forces

Patent metadata

Field	Value
Publication number	US-11802803-B2
Application number	US-202117461107-A
Country	US
Kind code	B2
Filing date	Aug 30, 2021
Priority date	Aug 28, 2020
Publication date	Oct 31, 2023
Grant date	Oct 31, 2023

Abstract

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.

First claim

What is claimed is:

1. An internal force transducer balance system comprising:
an internal balance configured for placement within a wind tunnel having a balance body extending axially along a longitudinal direction, the balance body having a metric interface portion at a first end and a non-metric interface portion at a second end of the balance body, the balance body further including 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; and
an integral fluid flow path that continuously extends from the first end to the second end of the balance body, wherein the integral fluid flow path is positioned in an interior core of the balance body and is routed through the axial strain measurement component of the internal balance,
wherein the integral fluid flow path comprises one or more turns as the integral fluid flow path is routed through the axial strain measurement component of the internal balance.

2. The system of claim 1 , wherein the balance body further includes a strain measurement component disposed between the axial strain measurement component and the metric interface portion of the balance body, wherein the strain measurement component is configured to measure one or more forces and moments applied to the internal balance in an orthogonal direction relative to a longitudinal axis of the internal balance.

3. The system of claim 1 , wherein the balance body of the internal balance further includes a strain measurement component disposed between the axial strain measurement component and the non-metric interface portion of the balance body, wherein the strain measurement component is configured to measure one or more forces and moments applied to the internal balance in an orthogonal direction relative to the longitudinal axis of the internal balance.

4. The system of claim 1 , wherein the balance body further includes a forward strain measurement component disposed between the axial strain measurement component and the metric interface portion of the balance body and a rear strain measurement component disposed between the axial strain measurement component and the non-metric interface portion of the balance body, wherein the forward and rear strain measurement components are configured to measure one or more forces and moments applied to the internal balance in an orthogonal direction relative to the longitudinal axis of the internal balance.

5. The system of claim 4 , wherein the internal balance is configured to directly measure six components of aerodynamic forces and moments applied to the internal balance and to measure aerodynamic interference forces applied to the internal balance as fluid flows through the integral fluid flow path of the internal balance.

6. The system of claim 4 , wherein the forward strain measurement component and the rear strain measurement component each comprise a plurality of structural tubes and a flexure membrane, wherein the plurality of structural tubes is coupled to the integral fluid flow path of the internal balance.

7. The system of claim 1 , further comprising:
a test model configured to be connected to the metric interface portion of the internal balance, wherein the integral fluid flow path of the internal balance is coupled to an internal fluid flow path of the test model.

8. The system of claim 7 , further comprising:
wind tunnel testing equipment having a sting element, wherein the sting element is connected to the non-metric interface portion of the internal balance, wherein the integral fluid flow path of the internal balance is coupled to an internal fluid flow path of the sting element.

9. The system of claim 8 , wherein the internal balance is configured to receive fluid from the sting element and route the fluid to the test model.

10. The system of claim 9 , wherein the internal balance is configured to measure three components of force and three moments applied to the internal balance.

11. The system of claim 10 , wherein the force is due to fluid flowing through the internal balance, wherein the fluid comprises pressurized air or gas.

12. An internal balance measurement method comprising:
providing an internal balance for a wind tunnel having a balance body extending axially along a longitudinal direction, the balance body having a metric interface portion at a first end and a non-metric interface portion at a second end of the balance body, the balance body further comprising 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, the balance body further comprising an integral fluid flow path that continuously extends from the first end to the second end of the balance body, wherein the integral fluid flow path is positioned in an interior core of the balance body and is routed through the axial strain measurement component of the internal balance, wherein the integral fluid flow path comprises one or more turns as the integral fluid flow path is routed through the axial strain measurement component of the internal balance;
connecting the metric interface portion of the internal balance to a test model, wherein the integral fluid flow path of the internal balance is coupled to an internal fluid flow path of the test model;
connecting the non-metric interface portion of the internal balance to a sting element of a wind tunnel testing equipment, wherein the integral fluid flow path of the internal balance is coupled to an internal fluid flow path of the sting element;
applying air flow over the test model while a fluid is applied to the integral fluid flow path via the sting element; and
measuring, via the axial strain measurement component, an axial force applied to the internal balance by the air flow over the test model and the fluid applied to the integral fluid flow path.

13. The method of claim 12 , wherein:
the balance body of the internal balance comprises a forward strain measurement component disposed between the axial strain measurement component and the metric interface portion of the balance body;
the balance body of the internal balance further comprises a rear strain measurement component disposed between the axial strain measurement component and the non-metric interface portion of the balance body; and
the forward strain measurement component and the rear strain measurement component are configured to measure one or more forces and moments applied to the internal balance in an orthogonal direction relative to the longitudinal axis of the internal balance.

14. The method of claim 13 , further comprising:
directly measuring three components of force and three moments applied to the internal balance.

15. The method of claim 14 , wherein the force is due to fluid flowing through the internal balance, wherein the fluid comprises pressurized air or gas.

16. The method of claim 12 , further comprising:
controlling a temperature or a flow rate of the fluid to reduce thermal gradients within the internal balance.

17. The method of claim 16 , wherein both the temperature and the flow rate are controlled to reduce thermal gradients within the internal balance.

18. The method of claim 12 , further comprising:
performing powered simulation testing on the test model using direct measurements obtained from the internal balance.

19. The method of claim 12 , wherein the test model comprises a planetary entry vehicle t

Assignees

• Nasa

Inventors

• Burns Devin E
• Parker Peter A

Classifications

• G01L19/0023 Primary

  for flowthrough systems having a flexible pressure transmitting element · CPC title

• G01L1/26

  Auxiliary measures taken, or devices used, in connection with the measurement of force, e.g. for preventing influence of transverse components of force, for preventing overload · CPC title

• G01L9/006

  of metallic strain gauges fixed to an element other than the pressure transmitting diaphragm · CPC title

• G01M9/062 Primary

  Wind tunnel balances; Holding devices combined with measuring arrangements · CPC title