Henry Nagamatsu

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 .

Experimental investigation of vibrational nonequilibrium in H2-O2 rocket engines

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

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

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.

A random distribution reacting mixing layer model

Spontaneous Raman spectroscopy was utilized in an experimental investigation of vibrational nonequilibrium in hydrogen-oxygen rocket engines. Oxygen temperatures were measured at subsonic, sonic, and supersonic portions of the nozzle flow. Rotational temperatures were determined from rotational Raman scattering. Both rotational and vibrational temperatures were determined from vibrational-rotational Raman spectra. Rotational temperatures from the two types of Raman scattering agree within the very large experimental error present. Vibrational temperatures are in agreement with rotational temperatures within the experimental error as well. Vibrational Raman spectroscopy is shown to be a valid means of estimating rotational temperatures within the rocket chamber and at low nozzle area ratios. Flowfield effects due to vibrational nonequilibrium are concluded to be minor. (Author)

Pressure measuring gage

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%.

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

A methodology for simulation of molecular mixing, and the resulting velocity and temperature fields has been developed. The ideas are applied to the flow conditions present in the NASA Lewis Research Center Planar Reacting Shear Layer (PRSL) facility, and results compared to experimental data. A gaussian transverse turbulent velocity distribution is used in conjunction with a linearly increasing time scale to describe the mixing of different regions of the flow. Equilibrium reaction calculations are then performed on the mix to arrive at a new species composition and temperature. Velocities are determined through summation of momentum contributions. The analysis indicates a combustion efficiency of the order of 80 percent for the reacting mixing layer, and a turbulent Schmidt number of 2/3. The success of the model is attributed to the simulation of large-scale transport of fluid. The favorable comparison shows that a relatively quick and simple PC calculation is capable of simulating the basic flow structure in the reacting and nonreacting shear layer present in the facility given basic assumptions about turbulence properties.