Cryogenic wind tunnels for aerodynamic testing springerlink. The results of this work indicate that cryogenic subsonic, transonic, and supersonic wind tunnels offer significant increases of test reynolds number without increases of aerodynamic load. Low and highspeed cryogenic testing of a wind tunnel. Application of doppler global velocimetry in cryogenic.
Handling room for windtunnel cryogenic models european. The facilitys cost was doubled in 1973 when modified to include a pilot cryogenic tunnel. For the investigation of force and torque data the icemodel was adapted to the half modelbalance of cryogenic wind tunnel cologne kkk. The currently developed boeing 787 was tested in the etw early on in the design process and the. The cryogenic wind tunnel has been introduced to provide the aerospace community with the means to test models at nearfullscale reynolds numbers, satisfying a particular need at transonic speeds. The more successful cryogenic tunnels reflect a skillful combination of cryogenic technology with wind tunnel technology. It is one of the worlds largest cryogenic wind tunnels.
Experimental investigation of reynolds number effects of. The cryogenic wind tunnel cologne kkk is a closed circuit low speed tunnel fig. Apr 18, 2008 the development of the cryogenic wind tunnel is one of many significant breakthroughs in both cryogenics and wind tunnel technology made during the past millennium. Sep 12, 2006 euro transonic, cryogenic wind tunnel in full swing. Materials for cryogenic wind tunnel testing internet archive.
Measurement and control temperature control of cryogenic wind. Temperature is one of the main variables need to be regulated in cryogenic wind tunnel to realize the true flight reynolds number. The reynolds number can be thus increased by a factor of 5. To achieve high reynoldsnumbers, the gas temperature in the tunnel circuit can be lowered down to 100 k by injecting liquid nitrogen. These investigations were carried out as a part of the cryogenic models technology program at larc.
Electret microphones, electronic equipment, and fairing material have been successfully tested by the authors under cryogenic conditions and have demonstrated longterm stability. Remarkably, one of the smallest such tunnels, just 1. Pdf tests for vehicle aerodynamics in the cryogenic wind tunnel. The more successful cryogenic tunnels reflect a skillful combination of cryogenic technology with windtunnel technology. Scaling techniques using cfd and wind tunnel measurements for. The earliest wind tunnels were invented towards the end of the 19th century, in the early days of aeronautic research, when many attempted to develop successful heavierthanair flying machines. As a result of the decreased velocity of sound as temperature is. The development of the cryogenic wind tunnel is one of many significant breakthroughs in both cryogenics and wind tunnel technology made during the past millennium. Multicomponent force balances for conventional and. The main advantages of the cryogenic option are highlighted. Ewald b, giesecke p, graewe e and balden th 1988 automatic calibration machine for internal cryogenic balances proc.
Pdf evaluation of hydrogen as a cryogenic wind tunnel test gas. Temperature control of cryogenic wind tunnel with a modified l1. Nov 22, 1994 a cryogenic model installed in the insulating box can be cooled down therein to the level of wind tunnel temperature or, if the model has already been in the wind tunnel, be maintained at the wind tunnel temperature. Cost effective use of liquid nitrogen in cryogenic wind. After a discussion of the tunnel specifications and performance, a general description of the facility is provided. A method of reliquefying from 12 to 19 of the nitrogen exhaust gas from a cryogenic wind tunnel has been developed. The background to the need for high reynolds number wind tunnels is outlined together with options.
Cryogenic wind tunnel is a sophisticated aerodynamics ground test facility, which operates in cryogenic temperature with injection of liquid nitrogen. I list in a table the main operating characteristics of the 20 cryogenic tunnels presently operational in 9 countries. Nasatm85805 19 stener oad tests and etention systems tests. Transonic aerodynamics wind tunnel testing considerations. Novel pressuresensitive paint for cryogenic and unsteady wind tunnel testing. Subsequently, acoustic array measurements performed in a cryogenic wind tunnel for various temperatures in the. The multivariable, nonlinear and coupled dynamics existing between the temperature, pressure and mach number in the tunnel, poses great challenges for the effective control of the tunnel. Technical feasibility and cost effectiveness of the system depends on performance of an innovative positive displacement expander which requires scale model testing to confirm design studies. Application of doppler global velocimetry in cryogenic wind. Perhaps the best solution to the problem of low reynolds number comes by operating a relatively big tunnel 2. Until recently engineers have been unable to reach full scale reynolds number in most wind tunnel tests. Since then, workers at research centers around the. Psp, tsp, model deformation systems, sc, ha, jet, pt, ss. Highreynoldsnumber cryogenic wind tunnel aiaa journal.
The proposed control method can be applied to wide range temperature operation of the tunnel by incorporating the nonlinear dynamic model of temperature into the controller design. The cryogenic wind tunnel cologne is a low speed wind tunnel. Pdf for decades, wind tunnel testing has been conducted in test section environments that. Pdf tests for vehicle aerodynamics in the cryogenic wind. Multicomponent force balances for conventional and cryogenic. Advances in cryogenic engineering, volume 39 advances in cryogenic engineering, issn 08861587. The european transonic wind tunnel etw is a highreynoldsnumber transonic wind tunnel using nitrogen as test gas. Marshall space flight centers 14 by 14inch transonic wind facility got its name because it can conduct tests in three speed regimes, from subsonic through transonic to supersonic. On the development of planar laser velocimetry techniques for. Advanced measurement techniques for high reynolds number. The wind tunnel was envisioned as a means of reversing the usual paradigm.
The development of the cryogenic wind tunnel is one of many significant breakthroughs in both cryogenics and windtunnel technology made during the past millennium. Novel pressuresensitive paint for cryogenic and unsteady. The degree of success of the various projects depends on many things. Cfd methods and cryogenic wind tunnel testing are typically being incorporated early in the process when designing a modern transonic transport. Drawings from this time period are identified as the wind tunnel balance calibration test stand, although later drawings still refer to 1242a as the propeller test stand. Nonlinear l 1 adaptive control of stagnation pressure in a. The history of the european transonic wind tunnel is briefly described. In this paper the test capability of this tunnel is analyzed and then some representative results are summarized. Cryogenic wind tunnels use evaporated liquid nitrogen as a test gas to decrease the tunnel temperature. By cooling the test gas down to 100k the reynolds number can be raised by a factor of 5. Via injection of liquid nitrogen, the wind tunnel can be operated in the range of 100 k cryogenic wind tunnel has been introduced to provide the aerospace community with the means to test models at nearfullscale reynolds numbers, satisfying a particular need at transonic speeds. Via injection of liquid nitrogen, the wind tunnel can be operated in the range of 100 k cryogenic wind tunnel.
The results of an investigation into the expected future use of the tunnel are summarised. Since then, workers at research centers around the world have started a large number of cryogenic windtunnel projects. Flow visualization of density in a cryogenic wind tunnel. The first cryogenic wind tunnel was a lowspeed tunnel built at the nasa langley research center in 1972. The measurements have been performed at the cryogenic wind tunnel at dlrs cologne site kryokanal koeln, kkk. Until recently, the problem of low test reynolds numbers has limited the usefulness of wind tunnels, especially at transonic speeds. Low and highspeed cryogenic testing of a wind tunnel model. Ewald b and balden th 1988 balance calibration and evaluation software proc. Design methodology for a quick and lowcost wind tunnel. The kkk is a continuous flow lowspeed wind tunnel with a 2. Section dynamic model of cryogenic wind tunnel gives a brief introduction of the facility, presents the nonlinear dynamics of cryogenic wind tunnel and the linear temperature model at nominal condition.
Etw was constructed and is operated by the four european countries france, germany, great britain and the netherlands. For aeronautical research the advantages of the cryogenic wind tunnel lie mainly in. Every model change requires the test section and model to be. Detection limits are determined for density measurements by using both unseeded rayleigh and raman n2 vibrational methods. Pdf measurement and assessment of wind tunnel flow quality. Cryogenic pressurized wind tunnels are expensive to use due to the use of liquid nitrogen ln, gaseous nitrogen gn, a very wide range in temperatures, circuit pressurization, dry air gn conditioning time, highly accurate wind tunnel models and very long model change times. Cryogenic tunnels are currently among the most advanced test facilities available. The large second generation of cryogenic tunnels astronautics and aeronautics, october 1971, pp. Since then, workers at research centers around the world have started a large number of cryogenic wind tunnel projects. Materials for cryogenic wind tunnel testing by tobler, r. Whereas most types of wind tunnels could operate with advantage at cryogenic temperatures, the continuousflow fandriven tunnel is particularly well suited to.
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