doi: 10.5028/jatm.2011. 03033111 João Batista P. Falcão Filho* Institute of Aeronautics and Space Experimental results from the São José dos Campos/SP – Brazil. [email protected] sounding vehicle Sonda III test Maria Luísa Collucci C. Reis campaign in the Pilot Transonic Institute of Aeronautics and Space São José dos Campos/SP – Brazil. Wind Tunnel [email protected] Abstract: The Pilot Transonic Wind Tunnel of the Institute of Aeronautics Algacyr Morgenstern Jr. and Space has conducted the first test campaign of a sounding vehicle, Institute of Aeronautics and Space São José dos Campos/SP – Brazil. Sonda III. The campaign is part of a project whose activities and final results [email protected] are presented in this paper. During the test campaign, many activities were performed to increase the productivity and accuracy of the tunnel. These activities included calibration procedures, corrective and preventive trials, * author for correspondence development of auxiliary devices, and theoretical and experimental analysis. Two tasks are described in details: the development and tests performed with the static pressure probe and the automatic re-entry flap actuation system. Several tests were carried out with the Sonda III at Mach numbers ranging from 0.3 to 1.0, at stagnation pressures of 70, 94, and 110 kPa. Experimental results include global aerodynamic coefficients (using internal balance) and pressure distribution over essential regions of the test article (using pressure sensitive paint technique). Keywords: Aerodynamics, Experimental results, Sonda III, Transonic Wind Tunnel. LIST OF SYMBOLS AND ACRONYMS PSP: Pressure sensitive paint q: Dynamic pressure, defined by 0.5ρ V 2 A: Cross sectional area of fuselage ∞ ∞ TTP: Pilot Transonic Wind Tunnel AEB: Brazilian Space Agency UNITAU: University of Taubaté ALA: Aerodynamics Division of IAE UNIVAP: University of Vale do Paraíba AEDC: Arnold Engineering Development Center USP: University of São Paulo CD: Drag coefficient VLS: Satellite Launch Vehicle CD0: Drag coefficient at zero angle of attack V : Velocity at free stream condition CFD: Computational fluid dynamics ∞ ρ : Static density at free stream condition CL: Lift coefficient ∞ σ : Standard deviation of Mach number Cm: Pitching moment coefficient M Cl: Roll moment coefficient INTRODUCTION Cn: Yawing moment coefficient CNPq: National Council for Scientific and The TTP of the IAE is a modern installation, built in Technological Development 1997 and made operational in 2002. The tunnel has a CY: Side force coefficient conventional closed circuit and is continuously driven by an 830 kW main axial compressor and an intermittent DCTA: Department of Aerospace Science and injection system, which operates in a combined mode, Technology for at least 30 seconds. Its test section is 300 mm wide EEI: Industrial Engineering College and 250 mm high, with slotted walls, and it has automatic FINEP: Brazilian National Agency for the Financing of stagnation pressure controls (from 50 to 125 kPa), Project and Studies Mach number (from 0.2 to 1.3), stagnation temperature IAE: Institute of Aeronautics and Space and humidity to properly simulate Mach and Reynolds ITA: Technological Institute of Aeronautics numbers (Falcão Filho and Mello, 2002). C : Reference length M: Mach number Figure 1 shows the operational envelope of the TTP, PIC: Programmable microcontroller in which the test capacity of the tunnel in terms of Reynolds numbers related to a typical reference chord of 27.4 mm can be seen. The TTP is a 1/8th scale of an Received: 10/07/2011 industrial transonic project. It was initially designed to Accepted: 04/10/2011 study the innovative features of the industrial facility, J. Aerosp.Technol. Manag., São José dos Campos, Vol.3, No.3, pp. 311-324, Sep. - Dec., 2011 311 Falcão Filho J.B.P. , Reis M.L.C.C., Morgenstern Jr. A. mainly concerning with the injection system operation in combination with the conventional main compressor operation. It was also designed to train the technical team to develop basic and academic research in high-speed regimes. Other activities include tests of vehicles with simple geometrical shapes, tests for the development of new aerodynamic transonic profiles, qualitative tests of airplanes with basic configurations, anemometric tests, amongst others. To accomplish this, the tunnel has three sets of six multi-component internal balances manufactured by MicroCraft™ for measuring forces and moments, four modules of 16 pressure channels scanners from PSI™ (2000) for pressure distribution tests, a Schlieren visualization system, hot-wire equipment, and PSP technique to determine pressure distribution over the Figure 2. Partial view of the TTP aerodynamic circuit. model surface. In addition, the tunnel possesses a two- dimensional probe positioning system, angle of attack remotely controlled system and re-entry flap capability whose objective was to achieve know-how about sounding (Falcão Filho et al., 2009). vehicles wind tunnel tests. Out of this amount, 48% were used in the product development, 47% in maintenance and Figure 2 shows a partial view of the aerodynamic circuit 5% in consumables. The campaign lasted 46 months in of the TTP along with some valves and tubing from the contrast to the 41 originally planned, and it used the tunnel auxiliary systems, and the structural frame in grey, which for an estimated 1,200 working hours. main compressor limit Thus, the TTP technical team conducted a test 0.5 T0 = 313 K campaign to assess the aerodynamic parameters of typical chord = 0.0274 m Sonda III, using an internal balance, and to investigate 0.4 INJECTION the pressure distribution using PSP (PSP technique) structural limit over important regions of the model, such as the ogive, 0.3 blow-off sonic throat the inter-stage area, and fins. The Sonda III vehicle limit operation 0.2 main compressor limit is a sounding rocket developed by the IAE. This is a turbining limit double stage vehicle with a 300 mm diameter second plenum 0.1 evacuation stage, capable of carrying a payload of approximately limit Reynolds number (millions) Reynolds 100 kg up to an altitude of 600 km. It is one of the 0 sounding rocket families named Sonda, which started 0 0.2 0.4 0.6 0.8 1 1.2 1.4 Mach Number with Sonda I, first launched in 1965. Sonda III was launched 27 times between 1976 and 2002. Two models Figure 1. The operational envelope of the TTP. were constructed to allow the installation of an internal balance inside the fuselage: a second stage model is used to open the plenum chamber door. Technical (scale 1:11) and a two-stage complete configuration details regarding the TTP can be found in Falcão Filho model (scale 1:20). The internal balance was fixed to and Mello’s (2002) paper. a sting structure to measure the model’s aerodynamic global parameters: forces (lift, CL, drag, CD and side, As a transonic wind tunnel, the TTP is a suitable tool to CY) and moments (pitching, Cm, roll, Cl and yawing, investigate important effects in the transition range (Goethert, Cn). General force and moment coefficients were 1961). Particularly for the IAE sounding vehicles, some calculated based on literature (Anderson, 2001), by physical phenomena can be more precisely assessed and Eq. 1 and 2: used for CFD code comparisons. This resulted in a proposal for a project, which was approved to run from 2007 to 2010. Force The AEB, by means of the VLS Associated Technology C = (1) Force q A Projects, sponsored the activities of a complete test campaign with the sounding vehicle Sonda III, named “Realização de Moment Ensaios do VS-30 no Túnel Transônico Piloto do IAE” (Tests CMoment = (2) q A C Development with VS-30 in the IAE Pilot Wind Tunnel). An amount of BRL 271,981.57 was provided for the project, where: 312 J. Aerosp.Technol. Manag., São José dos Campos, Vol.3, No.3, pp. 311-324, Sep. - Dec., 2011 Experimental results from the sounding vehicle Sonda III test campaign in the Pilot Transonic Wind Tunnel A is a reference area, herein adopted as the maximum During the test campaign, many activities were cross sectional area of the fuselage, performed to increase the tunnel’s productivity and C is a reference length, considered as the maximum accuracy of results. The present paper describes the fuselage diameter, and main steps followed in implementing the project and q is a reference dynamic pressure, calculated from the free some results obtained. stream parameters (density and velocity), and given by Eq. 3: PRELIMINARY TASKS 1 2 q = ȡ V (3) Several procedures were undertaken during the campaign 2 to better adapt the TTP for the proposed tests, which Figure 3 shows the scaled models utilized in the yielded important results that were then incorporated experiments, which have configurations of angle of fins into the installation. Four different categories can be equal to 0º, 2.5º and 5.0º. highlighted: (1) calibration procedures for the following: forced extraction mass flow from the plenum chamber, injection system operation with open and closed circuits, six-component internal balances with uncertainty determination, flow quality assessment in the test section, model’s angle of attack setting of the model, and positioning of the re-entry flaps; (2) corrective and preventive maintenance procedures for several components and subsystems to guarantee the perfect operation of the tunnel throughout the campaign, such as the main frequency inverter, auxiliary compressors of injection system, circuit pressure and humidity controls,