Hypersorption was recently developed by the Union Oil Company of California. The hypersorption process consists of a moving bed of an adsorbent passing counter currently to the gaseous flow. The gases are separated by selective adsorption. Of basic importance for successful operation is the heating of the adsorbent to obtain desorption. Considerable difficulty in achieving this transfer of heat is encountered because of the non-conducting nature of the adsorbent. The purpose of this investigation was to determine the heat transfer characteristics for the design of an improved heat exchanger for a moving bed system composed of air and activated carbon. This investigation was made studying the transfer of heat to five sizes of activated carbon, from 0.078 inches to fines, at flow rates of 2.2 to 11.0 pounds per hour. Steam at pressures of 15 to 75 pounds per square inch, gage, was used to heat the carbon moving through a three-quarter inch black iron pipe 36 inches long with an effective heating area of 0.65 square foot. The results of this investigation showed that the desorption of moisture in the activated carbon caused an unexpected break in the thermal conductivity curves between 200 and 220 °F, resulting in variable thermal conductivity-specific heat ratios. Rod-like flow was evidenced through e physical test, but poor correlation was observed between the date and the rod-like equation• The over·all heat transfer coefficient varied from one to three Btu per hour—square foot-°F per foot, increasing as the carbon flow rate and the Graetz number, KL/Wcp, increased. / Master of Science

Heat transfer to boiling liquids is of primary industrial importance. Surprisingly enough organized study of the variables which affect heat transfer to boiling liquids has been far less than proportional to the industrial usage of this type of heat transmission. Perhaps the least investigated phenomenon involved in heat transfer to boiling liquids is the so~called critical state or maximum in the rate of heat transfer-thermal driving force relationship. This maximum or peak is believed to be caused by a change in the type or method of heat transfer from the heating surface to the boiling liquid. The system is said to pass from a state of nucleate boiling through the maximum to a state of film boiling. The critical point is known to very for various liquids yet no adequate correlations were found which would provide a prediction of the characteristics of heat transfer for binary mixtures of liquids. In as much es ethanol and benzene are used extensively in industry they were selected for use in this investigation. The purpose of this investigation was to determine the characteristics of heat transfer from a horizontal silver surface to boiling mixtures of ethanol and benzene. A horizontal plate evaporator, with the necessary accessory equipment for measurement and control, was designed and constructed. The test liquids were prepared for concentrations of ethanol in benzene from 0 to 100 per cent in 10 volume per cent increments. These test liquids were charged to the evaporator and the characteristics of heat transfer determined by a series of steady state conditions of heat transfer. The rate of heat transfer was evaluated from the wattage input to the electrical heating unit. The temperature gradient between the heating surface and the main body of liquids was determined by evaluating the readings of thermocouples placed in the liquid space and the heater plate. The maximum rate of heat transfer was considered equivalent to the heat flux which caused the boiling system to shift through the maximum in the heat flux-temperature gradient relationship. The critical temperature gradient was obtained by an extrapolation of the heat flux-temperature gradient curve to maximum heat flux. The general conditions for the tests were: heat transfer surface, silver; cold liquid height in evaporator, 4—1/2 inches; evaporator diameter, 1·31/32 inches. The tests were made at normal atmospheric pressure which varied from 710.0 to 718.0 millimeters of mercury pressure. Steady state conditions of heat transfer were established before data was taken. / Master of Science

It was the intent of this investigation to determine boiling film coefficients of SO₂ in a temperature range not previously investigated. Further, a practical method of circulating liquid SO₂ and reclaiming SO₂ vapor without a compressor or pump was attained. For the range investigated the boiling film coefficients decreased with an increase in temperature difference between the boiIing SO₂ liquid and the surface of the heater. This occurred in the regime of partial nucleate boiling. Favorable comparisons were made with the limited information available for this bolling regime. It was found that the controlling film coefficient was on the steam side of the test evaporator. This was due to the comparatively large values obtained for SO₂ bolling film coefficients. Within the limits of this investigation, the overall heat transfer coefficient may be taken as approximately equal to the steam film coefficient. Much more work needs to be done in the regime of partial nucleate boiling as the available literature is far from complete. / Master of Science

Heat transfer experiments were done on a flat plate to study the effect of internal counter-flow backside cooling on adiabatic film cooling effectiveness and heat transfer coefficient. In addition, the effects of density ratio (DR), blowing ratio (BR), diagonal length over diameter (L/D) ratio, and Reynolds number were studied using this new configuration. The results are compared to a conventional plenum fed case. Data were collected up to X/D =23 where X=0 at the holes, an S/D = 1.65 and L/D=1,2. Testing was done at low L/D ratios since short holes are normally found in double wall cooling applications in turbine components. A DR of 2 was used in order to simulate engine-like conditions and this was compared to a DR of 0.92 since relevant research is done at similar low DR. The BR range of 0.5 to 1.5 was chosen to simulate turbine conditions as well. In addition, previous research shows that peak effectiveness is found within this range. Infrared (IR) thermography was used to capture temperature contours on the surface of interest and the images were calibrated using a thermocouple and data analyzed through MATLAB software. A heated secondary fluid was used as 'coolant' in the present study. A steady state heat transfer model was used to perform the data reduction procedure. Results show that backside cooling configuration has a higher adiabatic film cooling effectiveness when compared to plenum fed configurations at the same conditions. In addition, the trend for effectiveness with varying BR is reversed when compared with traditional plenum fed cases. Yarn flow visualization tests show that flow exiting the holes in the backside cooling configuration is significantly different when compared to flow exiting the plenum fed holes. We hypothesize that backside cooling configuration has flow exiting the holes in various directions, including laterally, and behaving similar to slot film cooling, explaining the differences in trends. Increasing DR at constant BR shows an increase in adiabatic effectiveness and HTC in both backside cooling and plenum fed configurations due to the decreased momentum of the coolant, making film attachment to the surface more probable. The effects of L/D ratio in this study were negligible since both ratios used were small. This shows that the coolant flow is still underdeveloped at both L/D ratios. The study also showed that increasing turbulence through increasing Reynolds number decreased adiabatic effectiveness. / MS / Gas turbine engines are used for multiple applications for power (power plants) or thrust (aircraft propulsion). Engine efficiency is correlated with higher working temperatures, which exceed the melting points of the materials being used. Therefore, more efficient cooling techniques are needed in order to protect the engine turbine components, such as blades and vanes. Relatively cooler air is bypassed from the compressor to the turbine section to cool the turbine components from the high temperatures. The air flows through the turbine components and out through machined holes referred to as film cooling holes. A protective layer, or film, protects the external region of the blade or vane. Previous research has found that the geometry of the airfoils used and the flow conditions play a major role in heat transfer. Most of the relevant research use a model that contains one-sided heat transfer. The present study focuses on combined backside and film cooling heat transfer, with different geometries and flow conditions, using a steady-state model for the data reduction procedure.

No description available.

No description available.

No description available.

The turbulence structure of convective heat transfer was studied experimentally in complex three-dimensional and separating turbulent boundary layers. Three test cases whose fluid dynamics have been well documented were examined. In case 1, time- and spatially-resolved surface heat transfer was measured in the nose region of a wing-body junction formed by a wing and a flat plate. Both the wing and the endwall were heated and held at a constant uniform temperature 20 °C above ambient temperature. Heat flux rates were increased up to a factor of 3 over the heat flux rates in the approach boundary layer. The rms of the heat flux fluctuations were as high as 25% of the mean heat flux in the vortex-dominated nose region. Away from the wing, upstream of the time-averaged vortex center, augmentation in the heat flux is due to increased turbulent mixing caused by large-scale unsteadiness of the vortex. Adjacent to the wing the augmentation in heat flux is due to a change in the mean velocity field. / Ph. D.

The heat transfer coefficient between a horizontal tube and a shallow fluidized bed of alumina particles (335-1261 micron) was measured, and the effects of the tube elevation (10-40 mm), static bed height (10-40 mm), and the design of the distributor were investigated. The cloud zone effect i.e. a sudden increase of the heat transfer coefficient when the tube was located right above the static bed height, has been verified as a feature of shallow bed systems; furthermore, the jet region has shown a dominant effect on the behavior of the shallow bed heat transfer. The results showed that the heat transfer coefficient increased monotonically with increasing air velocity when the tube was located in the jet region, and the heat transfer coefficient increased when a distributor which induced a deeper jet penetration was used. However, the erosion problem and the relatively high pressure drop across the distributor still need to be solved in further studies, so that the greatest economic value of a shallow bed can be achieved. / M. S.

This thesis describes the implementation of a two-dimensional heat transfer simulation system using a Splash-2 Custom Computing Machine (CCM). This application was implemented as a proof of concept for utilizing CCMs in the simulation of physical systems. This paper discusses physical systems simulation and the need for discretizing the domain of such systems, along with the techniques used for mathematical simulation. Also discussed is the nature of CCMs, and why they are well suited to this application. A detailed description of the approach and implementation is included to full document the design, along with an analysis of the performance of the resulting system. / Master of Science