The interest in aerodynamic heating problems has been increasing rapidly in the last decade. This interest is no longer concentrated on the heating of simple shapes for which adequate heat transfer theory has been developed« Because of the increasing Mach number ranges of aircraft, the need for information on the aerodynamic heating of various components has become imperative. Only when the magnitude of the problem has been exposed can the design for reducing the severity of local heating be optimized. Definition of these problems is of interest, not only because of the flow phenomena, but because of possible design limitations of re-entry vehicles and supersonic aircraft inlets, wings, rudders, etc.

The thesis is concerned with the design of an apparatus to determine the film coefficients for the conditions of forced convention, local boiling of sub-cooled water and the two phase flow of water-steam mixtures. Inasmuch as the agitating action of the bubbles during boiling of liquid permits high rate of heat transfer, information concerning convective heat transfer under conditions of local boiling and the two phase flow is of importance to the development of high heat flux heat exchangers which incorporate a phase change of coolant. The variation of the film coefficient with water temperature, flow rate, heat input rate, and fluid pressure may be investigated with this apparatus. The range of variables is Heat flux: 2.5 x 10⁵ to 5 x 10⁵ B/hr ft² Inlet temperature: 100 to 300°F Mass velocity: 0.52 x 10⁶ to 1.7 x 10⁶ 1b/hr ft² Pressure: Up to 200 psia The basic scheme of this apparatus is to pump deionized water through an electrically heard test section which is a stainless steel tub, 0.465 in O. D. x 0.020 in. thickness x 5ft length, where the fluid temperature, surface temperature and fluid pressure are measured by thermocouples and pressure gages. The electrical power to the test section is supplied by a welding transformed. Pressurization of the system is accomplished by throttling the flow at the discharge end of the test section through the exhaust valves. The fluid leaving the test section is condensed and sub-cooled by a vertical vapor-in-tube type heat exchanger so that the fluid can be recirculated again. An auxiliary ion-exchanger system is provided for deionization of the test water so that the deposition of scale on the heating surface can be prevented. With the above apparatus, local clause of fluid temperature, surface temperature and heat flux may be obtained and consequently a “point” determination of the film coefficient is possible. / M.S.

Assuming a polynomial of the fourth degree to describe the velocity function, the momentum integral equation for a second-order fluid is used to develop differential equations describing the boundary-layer for second-order flow past external surfaces. Using the momentum integral equation and appropriate boundary conditions, results are tabulated for both plane and axisymmetric stagnation flows. The effect of the second-order viscosity terms on the boundary-layer parameters for problems of flow past a circular cylinder and flow past a sphere is discussed. An interesting result is found in the case of flow past a sphere; for certain values of the second-order viscosity terms, there is a reduction in the viscous drag from that of Newtonian flow. / Master of Science

A theory is developed to explain the dependence of carrier transport in a thin semiconducting film on film thickness, magnetic field strength, and the dominant bulk scattering mechanism. This theory is based on the solution of the linearized Boltzmann equation in relaxation time form. The semiconductor is assumed to be bounded and nondegenerate with spherical energy surfaces and a scalar effective mass, It is also assumed to be flat banded with totally diffuse scattering at the surface. Classical Boltzmann statistics are used for equilibrium. The dependence of the relaxation time on the carrier energy is approximated by a power law equation. The principle improvement over similar theories is the treatment of the dependence of the relaxation time on carrier energy. The power law approximation for this dependence is valid for randomizing and elastic scattering mechanisms.

Sputtered thin films have the capability of producing a very random distribution of alloying elements within a host element. This study demonstrates the ability of the SQUID (Superconducting Quantum Undulating Interference Device) to measure the Curie temperature of thin films of Pd(1-x)Fe(x). The Curie temperatures of these films were found to be significantly less than bulk samples having the same iron concentration. The Curie temperature, furthermore, showed a systematic shift to higher values as the thickness of the film increased. Magnetic structure below the Curie temperature is revealed in magnetization and a.c. susceptibility curves for x=. 078. For other samples susceptibility data exhibited more sensitivity than magnetization in revealing magnetic detail below the Curie temperature. We attribute some of this magnetic detail to cluster glass behavior. / Ph. D.