Tanno, Hideyuki and Sato, Kazuo and Komuro, Tomoyuki and Takahashi, Masahiro and Itoh, Katsuhiro and Fujita, Kazuhisa and Laurence, Stuart and Hannemann, Klaus (2011) Force Measurement Using Non-Restrained Models in a Shock Tunnel. 7th European Symposium on Aerothermodynamics for Space vehicles, 9. Mai - 12. Mai 2011, Brugge, Belgien.
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A novel force measurement technique has been developed at the impulsive facility HIEST, in which the test model is completely non-restrained for the duration of the test, so it experiences free-flight conditions for a period on the order of milliseconds. This technique was demonstrated with a three-component aerodynamic force measurement with a blunted cone of total length 318 mm and a total mass of 22 kg. At the beginning of the wind tunnel test, the blunted cone test model was suspended from electromagnets fixed on the test-section ceiling. The model was released when a triggering signal arrived from the tunnel start signal. The model then fell so that it met the hypersonic test flow just as it arrived in the test section, and made a soft landing on a model catcher with four hydraulic shock absorbers. A miniature model-onboard data-logger, which was a key technology for this technique, was also developed in order to store the measured data. The data-logger was designed to be small enough to be instrumented in test models, with an overall size of 50 mm x 70 mm x 50 mm, including batteries. Since the logger was designed to measure force and pressure, it includes six piezoelectric amplifiers and four piezoresistive amplifiers, as well as high-speed analog-digital converters, which digitize the measured data with 16-bit resolution. The logger’s sampling rate and sample size are 500 kHz and 200 ms, respectively. The logger waits for a trigger signal (accelerometer output) and then starts to take measurements. The trigger threshold and pre-trigger delay time can be adjusted arbitrarily. Measured data is stored to static memory for transfer to a PC via a USB interface after a wind tunnel test. To demonstrate the entire measurement system, wind tunnel experiments were conducted in HIEST. In the present wind tunnel test campaign, records of pressure and axial force were obtained under conditions of H0 = 4 MJ/kg, P0 = 14 MPa. This demonstrated that the system worked correctly in the short test duration and harsh conditions typical of HIEST. Use of this data-logger allows the elimination of a large-diameter sting, ending concerns about the sting’s interference with the base flow of the model, which could cause serious errors in measurement in wind tunnel tests.
|Document Type:||Conference or Workshop Item (Speech, Paper)|
|Title:||Force Measurement Using Non-Restrained Models in a Shock Tunnel|
|In ISI Web of Science:||No|
|Series Name:||Conference Proceedings|
|Keywords:||Force and moment measurement, Hypersonic wind tunnel, on-board data-acquisition|
|Event Title:||7th European Symposium on Aerothermodynamics for Space vehicles|
|Event Location:||Brugge, Belgien|
|Event Type:||international Conference|
|Event Dates:||9. Mai - 12. Mai 2011|
|HGF - Research field:||Aeronautics, Space and Transport|
|HGF - Program:||Space|
|HGF - Program Themes:||Space Transport|
|DLR - Research area:||Raumfahrt|
|DLR - Program:||R RP - Raumtransport|
|DLR - Research theme (Project):||R - Raumfahrzeugsysteme - Anlagen u. Messtechnik|
|Institutes and Institutions:||Institute of Aerodynamics and Flow Technology > Spacecraft|
|Deposited By:||Dagmar Brennecke-Hosseinzadeh|
|Deposited On:||30 Nov 2011 11:53|
|Last Modified:||18 Jan 2012 12:04|
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