Joseph Kaye

Review of Industrial Applications of Heat Transfer to Electronics

Applications of heat transfer to electronic components and devices are presented and discussed. The major objectives are to review the state of the art in such applications and to indicate the need for a better grasp of the science of heat transfer in aiding the creative engineering of new electronic devices operating at extreme conditions of temperature, heat flux, air density, etc. The recent rapid growth of heat-transfer applications to electronics is analyzed in terms of the changing specifications resulting from the introduction of the supersonic and hypersonic aircraft and missiles. The general thermal problem of a given piece of electronic equipment is discussed and analyzed in terms of different modes of heat transfer. A simple method of comparing heat removal by means of natural convection, radiation, forced convection, and evaporative cooling is presented in chart form. The design philosophy of heat-transfer applications to industrial electronic equipment is discussed. Four specific illustrations of industrial applications of heat transfer to electronic components and equipment are presented. The first describes use of heat transfer and fluid mechanics to predict accurately the thermal performance of a newly developed vacuum tube which dissipates 25 kw. The second presents the analysis and some samples of the cold-plate technique used to cool highly compact miniaturized electronic equipment. The third example discusses the recent development of high temperature vacuum tubes, which can operate reliably at ambient temperatures in excess of 250°C. The final illustration discusses evaporatively-cooled magnetic components, in particular, transformers, by means of fluorochemical dielectrics.

Experimental Study of the Absolute Temperature Scale. XI. Deviation of the International Practical from the Kelvin Temperature Scale in the Range 0° to 444.6°C

The deviations of the International Practical Temperature Scale from the thermodynamic Celsius scale were determined at eleven temperatures in the range 0° to 444.6°C by a comparison of the indications of four platinum resistance thermometers with those of two constant‐volume nitrogen‐gas thermometers in a stirred‐liquid thermostat. In each gas thermometer several different ice‐point pressures were used to permit corrections to be made for the imperfection of the thermometric fluid. The arithmetic means of the observed differences between temperatures on the thermodynamic Celsius scale as it was defined in 1954 and those on the IPTS at the eleven temperatures, each weighted in accordance with the number of observations, are represented by the equation t(therm.)−t(Int.)=[−0.0060+(0.01t−1)(0.04106–7.363×10−5t)](0.01t), where t in the right‐hand member is on the IPTS. The standard deviation of a determination of Δt of unit weight from the equation is 18×10−4 deg.

Thermal Analysis of a Small D-C Motor; Part I. Dimensional Analysis of Combined Thermal and Electrical Processes [includes discussion]

A research program has been underway to study systematically small rotating electric machinery from the combined viewpoints of thermal and electrical processes. This paper is limited to the application of dimensional analysis to the detailed thermal and electrical processes occurring in the steady-state operation of a small d-c shunt-wound motor. Part II1 presents the numerous measurements of temperature distribution in the rotor and stator of such a motor made with the aid of 130 thermocouples and will correlate the experimental results in terms of dimensionless groups obtained with the aid of the dimensional analysis. Dimensional analysis was applied to this case of extremely complex and interrelated thermal and electrical processes and yielded a final single unknown functional relation between the important thermal and electrical parameters for the case of geometrically similar machines made from materials with identical electrical, magnetic, and thermal properties. The dimensionless groups which arose from this dimensional analysis were found to be of great value in planning the experimental test program and in correlating the experimental results. The dimensional analysis gave, however, no information as to the nature of the desired function relating the various dimensionless groups. The dimensional analysis was checked for the limiting case of zero internal flow of cooling air by a process of actually deriving the desired function predicted by dimensional analysis. This derivation combined equations for the electric circuit with the equations for the thermal circuit.

Thermal Analysis of a Small D-C Motor; Part II. Experimental Study of Steady-State Temperature Distribution in a D-C Motor with Correlations Based on Dimensional Analysis [includes discussion]

A research program has been under way to study systematically the combined thermal and electrical processes in small rotating electric machines. The previous paper in this series was limited to the application of dimensional analysis to such processes in a small d-c shunt-wound motor.1 This paper presents the results of extensive measurements of steadystate temperatures within such a motor, made with the aid of about 130 thermocouples. The details of the test motor, the procedures followed, the variables measured, and the results are described. For reasons of space, only eight selected temperature distributions are given from a total of 33 runs. The results for all the other important variables are shown in tabular form. The validity of the entire body of data was investigated in terms of a first-law balance or energy-flux balance for all processes occurring in the motor. The excellent balances obtained give great weight to the validity of the data. The experimental data in terms of the dimensionless parameters are fitted to simple empirical equations. The results are discussed from the point of view of prediction of size reduction for motors of the same design as the test motor, geometrically similar, and made from materials identical to those used for the test motor.

Simultaneous heat and mass transfer in the compressible laminar boundary layer of a dissociating gas

Abstract The velocity, temperature, and concentration profiles, the recovery factor, and the heattransfer coefficient were calculated for the case of the supersonic flow of a dissociating diatomic gas (iodine vapor) over a flat plate without a pressure gradient. Results were obtained for various mass-transfer rates. Exact values of the thermodynamic and transport properties were used in order to compare the results with estimates based on constant property solutions where the reference enthalpy method is used to calculate the state at which the properties were evaluated.