The use of fluidized solids techniques has been very prominent in recent years, especially in the petroleum industry with the increasing use of fluidized systems the need for the study of the relationships existing between the variables of such systems became more important. The application of the principles of dimensional and statistical analysis to such studies have proved very effective. The purpose of this investigation was to correlate the pressure drop across a fluidized bed of Ottawa sand with the variables of bed height, bed diameter, and particle size by dimensional and statistical means. In the investigation, the effects of bed height, particle size, and vessel diameter on the pressure drop through the fluidized system were studied. Copper fluidization columns were used having internal diameters of 2 and 4 inches. Standard testing grade of Ottawa sand were employed as the solid. The sand ranges studied were 20 to 30-, 30 to 50-, and 50 to 70-mesh (Tyler standard) with an absolute density of 166.6 pounds per cubic foot. Several bed heights of 1/2-, 1-, 1-1/2-, 1-, 1-1/2-, 3-, and 3-1/2-feet were used in the investigation with the static pressure drop determined at the critical mass velocity at each bed height. Air, varying in temperature from 68 to 76 degrees Fahrenheit and having a maximum humidity of 0.006 pound of water vapor per pound of dry air, was employed as the fluidizing medium. By means of dimensional and statistical analysis, an empirical equation was developed and the exponents relating pressure drop to the other properties of fluidized systems were evaluated. The equation applies only to velocities of the fluid at the critical mass velocity and is as follows: Y = 3.173 - 0.186X₁ + 0.039X₂ + 1.017X₃ - 0.297X₄ + 0.151X₅ Where: Y = log Δp/ρ_fD_t dimensionless X1 = log U_f/ √(gD_t) , dimensionless X2 = log D_p/D_t, dimensionless X3 = log L/D_t, dimensionless X4 = log ∈, dimensionless X5 = log μ_f/ρ_f√gD_t^3/2, dimensionless The pressure drop over the fluidized system was determined to be dependent primarily on the bed height of sand employed. The application of the principles of multiple regression showed that all the dimensionless groups correlated with pressure drop were significant. The pressure drop was shown to decrease as particle diameter decreased, increase as the tube diameter decreased, and increase as the bed height increased. / Master of Science

This proposes a model for a microwave heated fluidized bed by ceramic pellets to highlight the possibility to obtain a temperature gradient between the gas and the pellets. After a review of the recent work on microwave effects on chemical reactions, a short description of fluidization is given for a better understanding of the phenomena, followed by a development of a model of the heat transfer processes taking place in the fluidized bed. A parameter study describes the trends that should be expected despite the numerous restrictions and assumptions. Also, a set of parameters is proposed for optimal conditions that are close to the real conditions often encountered in practice. Numerous figures and tables are added, completing the main argument advanced in the thesis: it is possible to obtain a temperature difference between the gas and the pellets of a chemical bed reactor heated by microwaves by carefully choosing the following parameters: pellet diameter, bed height, gas velocity, pellet density and electric field. / Master of Science

Call number: LD2668 .T4 1964 D69 / Master of Science

Graduation date: 2004

Graduation date: 1995

Thesis (M.S.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains xi, 133 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 119-120).

Thesis (M.S.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains xiii, 97 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 72-74).

Hydrodynamic effects play important roles in fluidized bed combustion processes. Since the motion of "bubbles" is an important influence on fluidized bed heat transfer, a better understanding of their behavior is necessary for improving the design of fluidized bed boilers. Using a two-dimensional bed, silica sand particles were fluidized with air at room conditions. The bubbling bed was videotaped, and both qualitative and quantitative information were gathered. Bubble characteristics such as size, rise velocity and frequency were studied while particle size and superficial gas velocity were varied. Results were compared with some existing theories and other similar research. The effect of internal surfaces at several heights in the bed was also studied. General bubble behavior agreed well with descriptions from previous research, and the expected spherical-cap bubble shape was observed. Both bubble size and rise velocity increased with particle size and with fluid velocity. Bubble frequency increased with fluid velocity, but decreased with increasing particle size and height in the bed. These results agree with previous work done using optical probes to measure bubble characteristics. Comparisons of data with empirical models showed general agreement. The presence of internal surfaces had the effect of reducing the bubble size, rise velocity, and frequency, and also of reducing the influence of changing particle size and superficial velocity on the bed behavior. / Graduation date: 1992

Thesis (M.S.)--Rutgers University, 2009. / "Graduate Program in Mechanical and Aerospace Engineering." Includes bibliographical references (p. 78-79).

Thesis (Ph. D.)--Tampere University of Technology, 2002. / Includes bibliographical references. Also available on the World Wide Web.