Mechanical Engineering Commons^™

Laminar And Turbulent Natural Convection Heat Transfer In Trombe Wall Channels, Tony D. T. Chen

Mechanical & Aerospace Engineering Theses & Dissertations

The natural convective heat transfer and air movement in a Trombe wall solar passive system has been studied analytically and numerically. Three Trombe wall channel geometries including the parallel channel with axial inlet and exit, parallel channel with side vents and Trombe wall channel coupled to the room have been considered. Several models representing these Trombe wall geometries have been formulated. For the parallel channel with axial inlet and exit geometry, a momentum-integral method has been used to solve parabolic governing equations for two-dimensional laminar flow. This formulation leads to a second order ordinary differential equation for pressure defect in …

A Mathematical Model And Simulation Of Natural Circulation Loop Thermalhydraulics, Nihad E. Daidzic

Aviation Department Publications

In this work, a simple, nonlinear, seventh-order mathematical model with lumped parameter analysis of the thermalhydraulic processes in a natural circulation steam boiler loop is presented. Digital simulation has been performed in order to predict open loop transients in severe accidental situations. Parts of the circulation loop such as the steam drum, downcomer, and riser were modelled separately on the basis of the integral balance equations. The two-phase flow in the steam drum and in the riser was modelled with the aid of a homogeneous-equilibrium, two-phase flow model. Special care was taken to ensure the stability of the numerical scheme, …

Measurement Of The Coefficient Of Thermal Expansion Of Superconducting Thin Films Using Powder X-Ray Diffraction, Biju Chandran, R. Calvin Goforth, S. Nasrazadani

Journal of the Arkansas Academy of Science

The High Density Electronics Center (HiDEC) at the University of Arkansas, Fayetteville is developing the technology for High Temperature Superconductor Multi-Chip Modules (HTSC-MCM's). As part of this work, we are looking at the mechanical properties of HTSC materials. An important mechanical property which influences the mechanical integrity of the hybrid MCMis the coefficient of thermal expansion (CTE) of the HTSC films. As a first step in developing a procedure for the determination of the CTE of HTSC materials, the lattice parameters and the CTE of an alpha-alumina substrate have been determined by powder x-ray diffraction technique. An extension of this …

Experimental Study Of Pressure And Heating Rate On A Swept Cylindrical Leading Edge Resulting From Swept Shock Wave Interference, Christopher E. Glass

Mechanical & Aerospace Engineering Theses & Dissertations

An experimental study of the effects of leading edge sweep on surface pressure and heat transfer rate for swept shock wave interference is presented. This study was conducted as a cooperative agreement between NASA Langley Research Center and Calspan-University of Buffalo Research Center. Experimental tests were conducted in the Calspan 48-inch Hypersonic Shock Tunnel at a nominal Mach number of 8, nominal unit Reynolds number of 1.5 x 10⁶ per foot, leading edge and incident shock generator sweep angles of 0^o, 15^o, and 30^o, and incident shock generator angle-of-attack fixed at 12.5^{o …}

Viscous Shock Layer Analysis Of Hypersonic Flows Over Long Slender Vehicles, Kam-Pui Lee

Mechanical & Aerospace Engineering Theses & Dissertations

A method for solving the viscous shock-layer equations for hypersonic flows over long slender bodies is presented. The governing equations are solved by employing a spatial-marching implicit finite-difference technique. The two first-order equations, continuity and normal momentum, are solved simultaneously as a coupled set. This method yields a simple and computationally efficient technique.

Flows past hyperboloids and sphere cones with body half angles of five to 35 degrees are considered. The flow conditions included are from high Reynolds numbers at low altitudes to low Reynolds numbers at high altitudes. Detailed comparisons have been made with other predictions and experimental data …

A Turbulence Model For The Heat Transfer Near Stagnation Point Of A Circular Cylinder, Mounir B. Ibrahim

Mechanical Engineering Faculty Publications

A one-equation low-Reynolds number turbulence model has been applied successfully to the flow and heat transfer over a circular cylinder in turbulent cross flow. The turbulence length-scale was found to be equal 3.7y up to a distance 0.05δ and then constant equal to 0.185δ up to the edge of the boundary layer (wherey is the distance from the surface and δ is the boundary layer thickness).

The model predictions for heat transfer coefficient, skin friction factor, velocity and kinetic energy profiles were in good agreement with the data. The model was applied for Re ≤250,000 and Tu_{∞ …}

Computation Of 2-D And 3-D Natural Convection Heat Transfer In Closed And Vented Cavities, T. O. Mohieldin

Mechanical & Aerospace Engineering Theses & Dissertations

The natural convective heat transfer in closed and vented cavities has been studied numerically, using the primitive variables formulation. A two-and three-dimensional enclosure, and a two-dimensional Trombe Wall channel geometries are considered. The flow has been assumed to remain Laminar, and Boussinesq approximation is invoked for solving the governing equations, The finite-difference method used in this study, is based on the SIMPLER algorithm which uses a combination of central and upwind differencing scheme to obtain stable numerical results.

For both geometries, namely the closed and vented cavities, the fundamental nature of the fluid dynamic and heat transfer characteristics is revealed …

Convective Heat Transfer From Circular Cylinders Located Within Perforated Cylindrical Shrouds, Kamran Daryabeigi

Mechanical & Aerospace Engineering Theses & Dissertations

The influence of perforated cylindrical shrouds on the convective heat transfer to circular cylinders in transverse flow has been studied experimentally. Geometries studied were similar to those used in industrial platinum resistance thermometers. The influence of Reynolds number, ventilation factor (ratio of the open area to the total surface area of shroud), radius ratio (ratio of shroud's inside radius to bare cylinder's radius), and shroud orientation with respect to flow were studied.

The experiments showed that perforated shrouds with ventilation factors in the range 0.1 to 0.4 and radius ratios in the range 1.1 to 2.1 could enhance the convective …

Design Of A Combustion System Simulating Waste Heat Recovery From Diesel Engine Exhaust Gases, Nikolaos Papadopoulos

Mechanical & Aerospace Engineering Theses & Dissertations

A forced-draft laboratory combustion system simulating diesel engine exhaust gas volume flow rate and temperature conditions for waste energy recovery is analyzed and discussed. The system consists of a fan which supplies the air. The slightly compressed air is then ducted through a combustor where it is heated, and then to an air-quencher where it is cooled to a desired temperature. Finally, the air is sent through a heat exchanger, after a diffuser process, for waste heat recovery.

A gas dynamic analysis has been performed for each component part as well as a parametric study via a computer program in …

Retention Of Gasification-Combustion Products By Corn, S. W. Sizemore, Otto J. Loewer, Joseph L. Taraba, I. J. Ross, G. M. White

Biosystems and Agricultural Engineering Faculty Publications

Shelled corn was dried in layers of 5.1 cm (2 in.) 10.2 cm (4 in.), and 15.2 cm (6 in.) using air heated with the exhaust from a corn-cob fueled gasification-combustion updraft furnace. The drying air entering and leaving the grain layers was sampled for particulate content to determine the percentage of total particulates trapped by the grain during drying. It was determined that an average of 25% of the total particulates in the drying air were retained by the grain. The large majority of those particulates retained were found in the bottom 5.1 cm (2 in.) of the grain …

Experiments On Melting Around An Isothermal Horizontal Cylinder Under Computer Control, Timothy Moore Rothgeb

Mechanical & Aerospace Engineering Theses & Dissertations

The melting of a solid around an isothermal horizontal cylinder is a physical phenomenon which must be understood when attempting to design a latent heat storage system. The desire to design such a system is the motivating factor in this research. To gain this understanding of the fundamental melting processes several experiments were designed, and two sets of Stefan and Rayleigh number experiments were undertaken. Experiments were also performed to determine the properties of the paraffin that was used in these investigations. During the investigations of the melting processes, the temperature was measured at several locations throughout the liquid and …

On The Thermodynamics Of Solar Energy Use, Edward A. Fletcher

Journal of the Minnesota Academy of Science

Solar energy, coming from a 5800K heat reservoir, has thermodynamic advantages over fossil fuel combustion which are rarely recognized. This essay discusses the pertinent thermodynamics of chemical conversion processes. It points out the advantage of conducting endothermic processing at high temperatures and the unique character of sunlight as a source of process heat for high-temperature processing.

Saving Energy In Rural Maine : Or Who's Doing What On The Farm, Mane Department Of Agriculture

Maine Collection

Saving Energy In Rural Maine : Or Who's Doing What on the Farm

Compiled by Bettina M. Blanchard and Edited by Bill Seekins.

Maine Department of Agriculture, Food and Rural Resources, Division of Resources Development, Augusta, Maine, 1983.

Contents: List of Photographs and Diagrams / Introduction / Projects / 1. Wind / 2. Wood Heat Applications On the Farm / 3. Solar Applications / 4. Manure Handling and Waste Utilization / 5. Energy Efficient Cooling Methods / 6. Energy Saving In Field Operations / 7. Production and Use of Alternative Fuels / 8. Multi-Project Sites / Summary and Conclusions / …

A Passive Cooler For A Humid Climate, Steven Gilbert Ring

Retrospective Theses and Dissertations

This paper examine a passive cooling system for a humid climate. This system will be divided into two parts, a radiative system and an evaporative system combined into a roof pond system. Performance of the radiative system will be enhanced through the use of a selective cover which will make use of an atmospheric window between 8 and 13um. An attempt will also be made to thermally isolate the radiative system from convective gains with the evaporative system. The evaporative system will consist of a water, solvent and dye layer over the selective cover of the radiative system. The performance …

An Analytical Comparison And Contrast Of The Automobile Rotary Combustion Engine And The Reciprocating Engine, Eric K. Earle

Graduate Research Papers

The ReCE, although possessing many good characteristics as a motive source of power, is still somewhat far from achieving the desired efficiency in man's quest for better economical and practical means of transportation, due to the lack of higher speeds and its inability to burn all of the fuel admitted as a result of its large number of moving parts, their weight, size and reciprocating motion.

The design and development of the RCE has overcome many of the above problems inherent in the ReCE, and, therefore, has the potential of replacing the ReCE as the major source of automotive power …

A Method For Improving The Accuracy In Phase Change Heat Transfer Data Through Increased Precision In Thermophysical Property Determinations, John Philip Drummond

Mechanical & Aerospace Engineering Theses & Dissertations

Wind tunnel model materials typically have thermophysical properties that vary with both position and temperature. A numerical study using a finite difference representation of the heat conduction equation has been performed on several of these model materials to determine their thermal response under a specified heat loading. This study has confirmed the feasibility of using an effective thermophysical property to account for the existence of variable thermal properties when a model undergoes aero­ dynamic heating. The effective property, when used in the reduction of phase-change heat transfer data, forced agreement of the actual transient behavior of a model with the …

An Experimental Investigation Of The Vortex Sink Rate Sensors, Nelson L. Lu

Mechanical & Aerospace Engineering Theses & Dissertations

The vortex sink rate sensor device consists basically of an ideal sink flow between two coaxial disks. A sink tube was located at the center of one disk. The vortex was created by the rotation of the unit about its axis of symmetry. Five inch and 10 inch diameter of porous couplers were used for the air chamber here in this investigation. Several slenderness parameters, i.e., the ratio of the sink tube diameter to the height of the air chamber ^ro/n were conducted. Two probes were used to measure the static pressure and stagnation pressure respectively at various positions …

A Numerical Solution To The Problem Of Rotation Near The Ground, David D. Chen

Mechanical & Aerospace Engineering Theses & Dissertations

No abstract.

A Modified Copper Hot Water System, F J. Fielder

Journal of the Department of Agriculture, Western Australia, Series 4

A good supply of hot and boiling water for cleansing and sterilising utensils is essential for hygienic milk production.

Dairy Instructor F. Fielder, M.D.D., describes an efficient and economical modification of a copper hot water system for this purpose.

SINGLE copper units of 14 or 16 gallon capacity to supply hot and boiling water for the dairy are no longer good enough for most dairy farms.

A Shell-Theory Analysis Of Transient Thermal Stresses In Moderately Thick-Walled Cylinders, Thomas K. Mckinley

Mechanical Engineering ETDs

This paper investigates the validity of extending the concepts of shell theory to transient thermoelastic problems involving moderately thick-walled shells. The region of study is a moderately thick-walled cylinder which is constrained radially at both ends and is exposed to a uniform, time-dependent heating (or cooling) at one end. The cylinder walls are assumed to be adiabatic, and inertia effects are neglected in the development.

It is concluded from the results of this investigation that the extension of shell theory to moderately thick-walled cylindrical regions subjected to axial, time-dependent temperature variations is an analytical method of approach.

Australian Spark Arrester Tests : Test No. Spa-21 : Caterpillar D7 Turbocharger, W F. Baillie, G. H. Vasey

Journal of the Department of Agriculture, Western Australia, Series 4

FORMAL tests on spark arresters are conducted by The Tractor Testing Committee* at the Testing Station, Werribee, on behalf of those Companies concerned with tractors, engines or spark arresters who wish to have these equipments tested.

The arrester is tested on the engine it is specially designed for (as in this instance), or if it is sold for use on any or several engines, it is tested on an engine of the highest power for which the spark arrester is intended.

Australian Spark Arrester Tests : Spark Arrester For International B-250, W. F. Baillie, G. H. Vasey

Journal of the Department of Agriculture, Western Australia, Series 4

FORMAL tests on spark arresters are conducted by The Tractor Testing Committee at the Testing Station, Werribee, on behalf of those companies concerned with tractors, engines or spark arresters who wish to have these equipments tested.

Australian Spark Arrester Tests. Test No. Spa-5 : Caterpillar 3b-2655, W. F. Baillie, G. H. Vasey

Journal of the Department of Agriculture, Western Australia, Series 4

FORMAL tests on spark arresters are conducted by The Tractor Testing Committee* at the Testing Station, Werribee, on behalf of those companies concerned with tractors, engines or spark arresters who wish to have these equipments tested.

The arrester is tested on the engine for which it is specially designed or if this is not convenient (as in this instance) it is tested on an engine having the characteristics and power for which the spark arrester is intended.

Australian Spark Arrester Tests, W. F. Baillie, G. H. Vasey

Journal of the Department of Agriculture, Western Australia, Series 4

FORMAL tests on spark arresters are conducted by The Tractor Testing Committee at the Testing Station, Werribe, on behalf of those Companies concerned with tractors, engines or spark arresters who wish to have these equipments tested.

The arrester is tested on the engine it is specially designed for (as in this instance), or if it is sold for use on any or several engines, it is tested on an engine of the highest power for which the spark arrester is intended.

Australian Spark Arrester Tests : Spark Arrester For Fordson Dexta, W. F. Baillie, G. H. Vasey

Journal of the Department of Agriculture, Western Australia, Series 4

FORMAL tests on spark arresters are conducted by The Tractor Testing Committee at the Testing Station, Werribee, on behalf of those Companies concerned with tractors, engines or spark arresters who wish to have these equipments tested.

The arrester is tested on the engine for which it is especially designed or if this is not convenient, it is tested on an engine having the characteristics and power for which the spark arrester is intended.

I. Improved Ice Meltage In Ice Boxes; Ii. Temperature Control In Tents - Winter Phase., Robert Beaman Duggan

Electronic Theses and Dissertations

This thesis consists of two parts: Improved Ice Meltage in Ice Boxes; Temperature Control in Tents - Winter Phase. Improved ice meltage in the Progress refrigerator is discussed in the first part of the thesis. This portion of the work shows that satisfactory refrigerator temperatures and flat ice meltage could not be obtained simultaneously when using V-shaped ice racks, although they could be obtained separately; however, the basket-type chamber offers greater possibilities of obtaining proper temperatures and meltage characteristics. Series of tests are discussed and conclusions drawn from the results. In the second part of the thesis, a method of …

Portable Electric Home Milk Pasteurizers, A. E. Baragar, P. A. Downs

Nebraska Agricultural Experiment Station: Historical Research Bulletins

Two batch-type and one in-the-bottle type home milk pasteurizers were investigated to determine whether they comply with U.S. Public Health code temperature and time requirements for pasteurizers.

Further Studies Of Selected Types Of Domestic Gas Stoves, Arnold E. Baragar

Nebraska Agricultural Experiment Station: Historical Research Bulletins

This bulletin is a supplement to Nebraska Agricultural Experiment Station Research Bulletin 86. Tests were conducted in the same manner as were those described in Bulletin 86; hence, no reference has been made to experimental methods unless a test has not been previously reported. This paper is primarily concerned with (1) a discussion of cooking tops producing excessive carbon-monoxide gas, (2) more data relative to cooking-top burner efficiencies, (3) a further discussion of automatic lighters, and (4) a detailed study of ovens.

Factors Affecting The Performance Of Kerosene Cook Stoves, Edna B. Snyder

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The purpose of this investigation was to learn the effect of constructional details of the burner and the framework on the performance of kerosene stoves. Six stoves were used, four of the long-chimney type and two of the short-chimney type. Of the long-chimney burners, three were from the same manufacturer; the fourth was similar in appearance, but differed in performance. Of the short chimneys one burner used a wick, the other a lighting ring. The effect of: (1) draft variations and constructional details and (2) the framework on the heating time and thermal efficiency of stoves was studied.

A Study Of Kerosene Cook Stoves, Edna B. Snyder

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The purpose of this study was to learn the advantages and disadvantages of various types of kerosene cook stoves used in Nebraska. Kerosene cook stoves have burners of four types. Ten stoves representing the four types were studied as follows: four stoves having long-chimney wick burners; three stoves having short-chimney wick burners; two stoves having short chimneys with asbestos kindlers or lighting rings; one stove having wickless burners. To determine comparative performance of the four types of burners, they were tested for: (1) time required to heat a known quantity of water through a known range of temperature; (2) thermal …