Engineering topics

Kilgore, R. A.

Publications and source records attributed to Kilgore, R. A..

At least 19 records

NASA NTRS1988

Cryogenic wind tunnel research - A global perspective

The development of cryogenic wind tunnels is reviewed and 13 cryogenic wind tunnels currently operating in England, France, Germany, Japan, and the U.S. are described. A table illustrating the characteristics of these tunnels is presented, including test gases, test section sizes, speed ranges, stagnation pressure and temperature, and running time. The research conducted using the various wind tunnels is outlined and the operation of each of the tunnels is considered.

Dress, D. A.↗

NASA NTRS1986

Cryogenic wind tunnels for high Reynolds number testing

A compilation of lectures presented at various Universities over a span of several years is discussed. A central theme of these lectures has been to present the research facility in terms of the service it provides to, and its potential effect on, the entire community, rather than just the research community. This theme is preserved in this paper which deals with the cryogenic transonic wind tunnels at Langley Research Center. Transonic aerodynamics is a focus both because of its crucial role in determining the success of aeronautical systems and because cryogenic wind tunnels are especially applicable to the transonics problem. The paper also provides historical perspective and technical background for cryogenic tunnels, culminating in a brief review of cryogenic wind tunnel projects around the world. An appendix is included to provide up to date information on testing techniques that have been developed for the cryogenic tunnels at Langley Research Center. In order to be as inclusive and as current as possible, the appendix is less formal than the main body of the paper. It is anticipated that this paper will be of particular value to the technical layman who is inquisitive as to the value of, and need for, cryogneic tunnels.

Lawing, P. L.↗

NASA NTRS1986

Optimum transonic wind tunnel

The optimum facility to complement existing high Reynolds number transonic wind tunnels is discussed. It is proposed that the facility be cryogenic, have a total pressure of five atmospheres or less, and have a test section on the order of 4- to 5-meters square. The large size is to accommodate complicated models such as those used in propulsion testing. It is suggested that magnetic suspension and wall interference minimization and correction procedures be used. Simplicity of initial design is stressed as a means of providing for future growth opportunities.

Barnwell, R. W.↗

NASA NTRS1985

A survey of cryogenic wind tunnels

Following the development of the cryogenic wind tunnel at the NASA Langley Research Center in 1972, a large number of cryogenic wind-tunnel projects have been undertaken at various research establishments around the world. The purpose of this paper is to describe some of the more significant of these projects. Described in this paper are cryogenic wind-tunnel projects in China (CARDC), England (College of Aeronautics at Cranfield, RAE-Bedford, and University of Southampton), 'Europe' (Pilot European Transonic Windtunnel at NAL-Amsterdam, and the European Transonic Windtunnel proposed for DFVLR-Koeln), France (ONERA-CERT), Germany (DFVLR-Koeln, and DFVLR-Goettingen), Japan (NAL, University of Tsukuba, and National Defense Academy), Sweden (Rollab), and the United States (Douglas Aircraft Co., University of Illinois at Urbana-Champaign, and NASA-Langley).

Kilgore, R. A.↗

NASA NTRS1985

The NASA Langley 0.3-m transonic cryogenic tunnel

The Langley 0.3-m Transonic Cryogenic Tunnel (0.3-m TCT) can operate from ambient to cryogenic temperatures at absolute pressures from 1 to 6 bars. Since the 0.3-m TCT began operation in 1973, it has been used to develop instrumentation and operating techniques for cryogenic tunnels as well as for aerodynamic tests where advantage can be taken of the extremely wide range of Reynolds number available. This paper describes the present capabilities of the 0.3-m TCT and gives an overview of recent research activities which include both steady and unsteady testing. Emphasis is given to safety and the development of testing techniques for cryogenic tunnels. Results of studies aimed at establishing the lower limits of operating temperature are presented and the impact of these studies on tunnel operation is discussed. Finally, the design features and operating characteristics of a new self-streamlining wall test section recently installed in the tunnel circuit are described.

Kilgore, R. A.↗

NASA NTRS1985

Other cryogenic wind-tunnel projects

Following the development of the cryogenic wind tunnel at the NASA Langley Research Center in 1972, a large number of cryogenic wind-tunnel projects have been undertaken at various research establishments around the world. Described in this lecture are cryogenic wind-tunnel projects in China (Chinese Aeronautical Research and Development Center), England (College of Aeronautics at Cranfield, Royal Aircraft Establishment - Bedford, and University of Southampton), Japan (National Aerospace Laboratory, University of Tsukuba, and National Defense Academy), Sweden (Rollab), and the United States (Douglas Aircraft Co., University of Illinois at Urbana-Champaign, and NASA Langley).

Kilgore, R. A.↗

NASA NTRS1985

Description of the insulation system for the Langley 0.3-Meter Transonic Cryogenic Tunnel

The thermal insulation system of the Langley 0.3 Meter Transonic Cryogenic Tunnel is described. The insulation system is designed to operate from room temperature down to about 77.4 K, the temperature of liquid nitrogen at 1 atmosphere. A detailed description is given of the primary insulation sytem consists of glass fiber mats, a three part vapor barrier, and a dry positive pressure purge system. Also described are several secondary insulation systems required for the test section, actuators, and tunnel supports. An appendix briefly describes the original insulation system which is considered inferior to the one presently in place. The time required for opening and closing portions of the insulation system for modification or repair to the tunnel has been reduced, typically, from a few days for the original thermal insulating system to a few hours for the present system.

Lawing, P. L.↗

NASA NTRS1984

An external insulation system for a cryogenic wind tunnel

The thermal insulation system of the 0.3-Meter Transonic Cryogenic Tunnel (0.3-m TCT) at the NASA Langley Research Center is described in text, photographs, and drawings. The system is designed to operate from room temperature down to about 77.4 K, the temperature of liquid nitrogen at 1 atmosphere. A detailed description is given of the primary insulation system which consists of glass fiber mats, a 3-part vapor barrier, and a dry nitrogen positive-pressure purge system. Also described are several secondary insulation systems required for the test section, actuators, and tunnel supports. An appendix briefly describes the original insulation system which is considered inferior to the one presently in place. Time required for opening and closing portions of the insulation system for modification or repair to the tunnel has been reduced, typically, from a few days for the original thermal insulating system to a few hours for the present system.

Dress, D. A.↗

NASA NTRS1984

The application of cryogenics to high Reynolds number testing in wind tunnels. II - Development and application of the cryogenic wind tunnel concept

The development and application of the cryogenic wind tunnel concept at the Langley Research Center are described. Particular attention is given to the low-speed cryogenic tunnel and the pilot transonic cryogenic tunnel. The major conclusions with respect to the operation and performance of the pilot transonic cryogenic tunnel after almost 4000 h of operation at cryogenic temperatures are that: (1) purging, cooldown, and warm-up times are acceptable and can be predicted with good accuracy, and that (2) the quantity of liquid nitrogen required for cooldown and running can be predicted with good accuracy. The U.S. National Transonic Facility is described in detail.

Kilgore, R. A.↗

NASA NTRS1984

The application of cryogenics to high Reynolds number testing in wind tunnels. I - Evolution, theory, and advantages

During the time which has passed since the construction of the first wind tunnel in 1870, wind tunnels have been developed to a high degree of sophistication. However, their development has consistently failed to keep pace with the demands placed on them. One of the more serious problems to be found with existing transonic wind tunnels is their inability to test subscale aircraft models at Reynolds numbers sufficiently near full-scale values to ensure the validity of using the wind tunnel data to predict flight characteristics. The Reynolds number capability of a wind tunnel may be increased by a number of different approaches. However, the best solution in terms of model, balance, and model support loads, as well as in terms of capital and operating cost appears to be related to the reduction of the temperature of the test gas to cryogenic temperatures. The present paper has the objective to review the evolution of the cryogenic wind tunnel concept and to describe its more important advantages.

Kilgore, R. A.↗

NASA NTRS1984

Cryogenic wind tunnels for high Reynolds number testing

The evolution and early development of cryogenic wind tunnels is reviewed, and consideration is given to current and future research in cryogenic wind tunnel testing. Emphasis is placed on the problem of low Reynolds numbers in current cryogenic wind tunnel tests as well as flow instability, wall interference and support interference which can inhibit a reliable simulation of complex three-dimensional flows. The operating characteristics of several of the worlds low-speed and high-speed cryogenic wind tunnel testing facilities are presented in the form of several graphs and photographs.

Kilgore, R. A.↗

NASA NTRS1983

Cryogenic wind tunnels for high Reynolds number testing

The present investigation has the objective to provide an overview of the development of cryogenic wind tunnels and their application to high Reynolds number testing. The current need for wind tunnels reflects the fact that many complex three-dimensional flows cannot yet be adequately dealt with analytically. Imperfections of wind tunnels are partly related to the fact that for most wind tunnel tests the Reynolds number is much too low. The best solution to this problem appears to be an operation of the tunnel at cryogenic temperatures (arbitrarily defined as temperatures of 150 K or less. In addition to decreasing the temperature, there are three other approaches for increasing the Reynolds number. These approaches include the use of a heavy gas, an increase in the model size, and an increase in pressure. Attention is given to the variable density tunnel concept, problems with high dynamic pressures, low-speed cryogenic tunnel results, transonic cryogenic tunnel tests, and the injection of liquid nitrogen into the tunnel.

Kilgore, R. A.↗

NASA NTRS1982

The cryogenic wind tunnel for high Reynolds number testing

An improved way to increase the Reynolds numbers capability of wind tunnels has been developed at the Langley Research Center. Cooling the test gas to cryogenic temperatures by spraying liquid nitrogen into the tunnel circuit increases Reynolds number with no increase in dynamic pressure and a reduction in drive power. In addition, the ability to vary the temperature of the test gas independently of pressure and Mach number allows for the first time the independent determination of Reynolds number, Mach number, and aeroelastic effects. A new fan-driven transonic cryogenic tunnel being built at the Langley Research Center will provide an order of magnitude increase in Reynolds number capability over existing transonic tunnels in the United States when it is completed later this year.

Kilgore, R. A.↗

NASA NTRS1982

The cryogenic wind tunnel for high Reynolds number testing

The development of cryogenic wind tunnels is reviewed with reference to the theory and advantages of cryogenic tunnels, problems common to wind tunnels and their solution, and application of cryogenic wind tunnels to high Reynolds number testing. It is shown that cryogenic wind tunnels can achieve full-scale Reynolds number with reasonable tunnel size, dynamic pressure, and drive power; the use of such tunnels also makes it possible to separate the effects of Reynolds number, Mach number, and aeroelasticity. Application of the cryogenic tunnel concept is illustrated by three examples, namely an atmospheric low-speed cryogenic tunnel, a 0.3-meter transonic cryogenic tunnel, and the National Transonic Facility now nearing completion.

Kilgore, R. A.↗

NASA NTRS1981

Model experience in the Langley 0.3-m transonic cryogenic tunnel

The model building, development, and testing experience gained during 8 years of operation of the 0.3-m Transonic Cryogenic Tunnel (TCT) is summarized. The summary is divided into four portions: (1) models tested in the 0.3-m TCT's original octagonal test section; (2) models tested in the present two dimensional test section; (3) models tested as a part of tunnel calibration and the development of advanced technology airfoils; and (4) development of a new way to construct two dimensional airfoil models. Design requirements imposed on the models by high Reynolds number testing at cryogenic temperatures are reviewed.

Lawing, P. L.↗

NASA NTRS1981

Instrumentation for calibration and control of a continuous-flow cryogenic tunnel

Aspects of selection and application of calibration and control instrumentation that are influenced by the extremes in the temperature environment to be found in cryogenic tunnels are described. The instrumentation and data acquisition system used in the 0.3-m transonic cryogenic tunnel along with typical calibration data obtained in a 20 by 60 cm two dimensional test section are described.

Ladson, C. L.↗

NASA NTRS1980

Model design and instrumentation experiences with continuous-flow cryogenic tunnels

The development of wind tunnels that can be operated at cryogenic temperatures has placed several new demands on the ability to build and instrument wind tunnel models. The experiences at the NASA Langley Research Center relative to the design and instrumentation of models for continuous flow cryogenic wind tunnels are reviewed.

Kilgore, R. A.↗

NASA NTRS1980

Selection and application of instrumentation for calibration and control of a continuous-flow cryogenic tunnel

Selection and application of calibration and control instrumentation influenced by the extremes in the temperature environment to be found in cryogenic tunnels are described. The instrumentation and data acquisition system used in the Langley 0.3 m transonic tunnel are described along with typical calibration data obtained in a 20 by 60 cm two dimensional test section.

Kilgore, R. A.↗