Leik Myrabo

EXPERIMENTAL INVESTIGATION OF 2-D ION MOBILITY ENDOATMOSPHERIC DRIVE (IMED)

An experimental study of the Ion Mobility Endoatmospheric Drive (IMED) was performed. This subsonic air-breathing propulsion system is achieved by using a thin positively charged wire to generate positive ion clouds in the air in front of a conductive vehicle hull, while simultaneously charging the hull negatively. This gives rise to a strong electric field established between the positive ion cloud and the hull. The positive ions are accelerated in the electric field and thrust is generated by means of collisional processes with neutral air molecules. Recent project achievements include the experimental proof of the feasibility for IMED propulsion using a cylindrical hull geometry. The thrust and coupling coefficient of this thruster setup have been measured for the following electrode configurations: 1 ) cylindrical and airfoil-shaped hulls sporting one or two wires; 2) different wire diameters; 3) different anode-to-cathode distances; and, 4) different leading-edge hull diameters at various current and voltage inputs. Also, two independent experimental procedures were devised to measure the thrust. Despite some shortcomings, the independently determined thrust levels did agree. One of these procedures used a hotwire to measurc wake flow velocity profiles: the hotwire system was calibrated to extremely low velocities by a low speed. dynamic calibration technique described in this paper.

Drag of shroud deployment bladder at Mach numbers of 8 to 20

STRACT’ An investigation ‘of a Shroud Deployment System (SDS) bladder was conducted in the Rensselaer Polytechnic Institute 2+in .Hypersonic Shock Tunnel. The cut-rem investigation experimentally determined the axial drag coefficient for the bladder, while attached ~0 .

Laboratory Facilities and Measurement Techniques for Beamed‐Energy‐Propulsion Experiments in Brazil

he SDS d-ge support, for nominal Mach numbers of 8 to 20 and stagnation temperatures up to 7400 “R Me&ements were made of the pitot pressure and the force applied to the bag by the j~ypynjc: ,flqw. i 10.. <obtain the high stagnation ‘~mpe~~~..~ tunnel was ,oper

Airbreathing Hypersonic Laser Thermal Propulsion Experiments with a LightCraft Vehicle - Status Update

ted in equilibtium interface mode, w.@e. the lower temperatures were achieved by ope@ing in the reflected ,We. The experimental results were not in general agreement with Lockheed-Martin’s’ SIMP code solution. The SIMP code computatiori model did not include the dunnage. The leading edge of the dtmnage was incorporated into the experimental model to more accurately simulate realistic flow characteristics. The additional shock waves produced by the dunnage and their interaction with the bow shock wave created by the bladder had a severe effect on the drag coefficient.

Aerodynamic shear load on shroud deployment bladder struts in the RPI High Pressure Shock Tube

Laser propulsion is an innovative concept of accessing the space easier and cheaper where the propulsive energy is beamed to the aerospace vehicle in flight from ground—or even satellite‐based high‐power laser sources. In order to be realistic about laser propulsion, the Institute for Advanced Studies of the Brazilian Air Force in cooperation with the United States Air Force and the Rensselaer Polytechnic Institute are seriously investigating its basic physics mechanisms and engineering aspects at the Henry T. Hamamatsu Laboratory of Hypersonic and Aerothermodynamics in Sao Jose dos Campos, Brazil. This paper describes in details the existing facilities and measuring systems such as high‐power laser devices, pulsed‐hypersonic wind tunnels and high‐speed flow visualization system currently utilized in the laboratory for experimentation on laser propulsion.

Experimental pressure investigation of a 'Directed-Energy Air Spike' inlet at Mach 10

A laser-propelled transatmospheric vehicle experiences the full spectrum of flight regimes, from subsonic to hypersonic, along its Earth-to-Orbit (ETO) trajectory. A 2-D model of a laser propelled LightCraft was tested in the T3 Hypersonic Shock Tunnel (HST) at the Henry T. Nagamatsu Laboratory for Aerothermodynamics and Hypersonics. The test campaign began with no flow, ambient (1 bar) conditions, and transitioned to medium enthalpy HST runs at Mach number of 9.0. The model was instrumented with piezoelectric pressure transducers to measure the time dependent pressure distributions. A high speed digital Schlieren imaging system recorded the time-dependent flowfield evolution inside the LightCraft absorption chamber, following pulsed laser energy deposition. This data was also compared with blast wave arrival at numerous pressure transducers distributed along the 2D engine centerline. A Lumonics TEA 622 laser system with an unstable resonator cavity emitted 1 μs, 200 J pulses (low divergence, 90ns FWHM) into the 0.6 m diameter HST test section.

Experimental heat transfer investigation of 'Directed-Energy Air Spike' inlet at Mach 10

Aerodynamic shear loading tests were conducted on two different designs of the Shroud Deployment System (SDS) bladder in the RPI 24-m diameter High Pressure Shock Tube. The objective of this test was to determine the maximum aerodynamic shear load the shroud ejection bladders (series -301 and -303) could withstand before being sheared off the substructure. The bladders were subjected to impulsive loading by applying various strength shock waves. The strength of the shock waves were varied by changing the ratio of driven and driver tube pressures. The deployment bladder was mounted at the exit of the shock tube in the 200-fi3 dump tank on a double strut confIguration. The maximum total pressures at failure were 404 psi for model -301 and 475 psi for model -303 f5.25%.