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(1 - 7 of 7)
- Title
- THEORETICAL ANALYSIS OF HEAT EXCHANGERS IN AN OCEAN THERMAL ENERGY CONVERSION SYSTEM.
- Creator
- BENTON, DUDLEY JAMES., Florida Atlantic University, Tennant, Jeffrey S.
- Abstract/Description
-
A theoretical study was conducted to determine the relationships between the major controlling factors in the heat exchangers in an Ocean Thermal Energy Conversion system. A digital computer model was developed to simulate and analyze the system. Variations in the thermophysical properties of the seawater and working fluid were considered in the analysis. Effects of variation in excess temperature differential on phase change heat transfer rates were also considered. The net power output of...
Show moreA theoretical study was conducted to determine the relationships between the major controlling factors in the heat exchangers in an Ocean Thermal Energy Conversion system. A digital computer model was developed to simulate and analyze the system. Variations in the thermophysical properties of the seawater and working fluid were considered in the analysis. Effects of variation in excess temperature differential on phase change heat transfer rates were also considered. The net power output of the system was determined from a Rankine cycle analysis. The results of this investigation show the necessity of a Rankine cycle analysis and the inclusion of fluid property variations. A significant difference can be seen in the net power output of such a system per dollar invested in the heat exchangers projected by this analysis and the analysis of other investigators which have not considered these factors.
Show less - Date Issued
- 1977
- PURL
- http://purl.flvc.org/fcla/dt/13875
- Subject Headings
- Heat exchangers--Fluid dynamics, Ocean thermal power plants
- Format
- Document (PDF)
- Title
- Utilizing "bills" for drag reduction below transition on spherical bodies.
- Creator
- Adamson, James Edward., Florida Atlantic University, Tennant, Jeffrey S.
- Abstract/Description
-
Russian experimenters Kozlov and Leonenko have reported substantial drag reduction on a sphere using a "bill" or "spike" extending from the body upstream into the flow. A systematic series of experiments was conducted to determine the extent of the reduction and to identify the parameters of the reported drag reduction effect. The tests were performed in the Florida Atlantic University Ocean Engineering Department's Aerolab wind tunnel. A sphere was fitted with tapering bills of various...
Show moreRussian experimenters Kozlov and Leonenko have reported substantial drag reduction on a sphere using a "bill" or "spike" extending from the body upstream into the flow. A systematic series of experiments was conducted to determine the extent of the reduction and to identify the parameters of the reported drag reduction effect. The tests were performed in the Florida Atlantic University Ocean Engineering Department's Aerolab wind tunnel. A sphere was fitted with tapering bills of various lengths, base diameters, and bill/sphere fillet radii. Experiments indicated that the effect was restricted to Reynolds numbers below 4.0 x 10^5 and that the drag of the sphere/spike combination was actually increased at Reynolds numbers greater than this. A smoke generator was used to visualize the drag reduction mechanism, which appears to be a recirculating cell at the base of the sphere/spike intersection.
Show less - Date Issued
- 1989
- PURL
- http://purl.flvc.org/fcla/dt/14514
- Subject Headings
- Drag (Aerodynamics), Wind tunnel models
- Format
- Document (PDF)
- Title
- AN EXPERIMENTAL STUDY OF BIOFOULING ON A FLAT PLATE SUSPENDED IN A UNIFORM FLOW.
- Creator
- WOOD, MARK ALAN., Florida Atlantic University, Tennant, Jeffrey S., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
An investigation was conducted to determine the relationship between hydrodynamic boundary layer parameters and biofouling growth rates. A summary of previous investigations of hydrodynamic effects on biofouling is presented. Wall shear stress is shown to be an important parameter and is described in detail. A submersible water tunnel was designed to allow investigation of a flat plate subject to a uniform flow of seawater. Parallel flow past a flat plate with a laminar boundary layer was...
Show moreAn investigation was conducted to determine the relationship between hydrodynamic boundary layer parameters and biofouling growth rates. A summary of previous investigations of hydrodynamic effects on biofouling is presented. Wall shear stress is shown to be an important parameter and is described in detail. A submersible water tunnel was designed to allow investigation of a flat plate subject to a uniform flow of seawater. Parallel flow past a flat plate with a laminar boundary layer was used to ensure that experimental conditions existed in which a known wall shear stress distribution was establised. Tests were conducted off Virginia Key in Miami, Florida. The results of the experiments clearly indicate the existance of a threshold value of shear stress which inhibits the attachment of the macrofouler under study, the acorn barnacle (Balanus spp.). Reported growth rates from other investigations are presented to substantiate results. Recommendations are made for additional hydrodynamic investigations in dealing with biofouling.
Show less - Date Issued
- 1977
- PURL
- http://purl.flvc.org/fcla/dt/13849
- Subject Headings
- Fouling, Hydrodynamics
- Format
- Document (PDF)
- Title
- A BED-LOAD TRANSPORT MEASURING DEVICE.
- Creator
- WU, MUO-CHUNG., Florida Atlantic University, Tennant, Jeffrey S., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The objectives of this investigation were: (1) to find the relationship between the sand movement velocity and the force induced using a small model basin, (2) to find and build a sand transport meter and apply the relation from (1) together to measure the velocity fluctuation and quantity of sand movement on the beach. The idea of model basin comes from the fluidized bed concept. Using this model, the complicated influences that happen during the field measurement can be prevented, and a...
Show moreThe objectives of this investigation were: (1) to find the relationship between the sand movement velocity and the force induced using a small model basin, (2) to find and build a sand transport meter and apply the relation from (1) together to measure the velocity fluctuation and quantity of sand movement on the beach. The idea of model basin comes from the fluidized bed concept. Using this model, the complicated influences that happen during the field measurement can be prevented, and a prime relation can be applied to the field measurement. In the model basin experiment, the force induced by the drag is related to the velocity of power around 0. 62. In the field measurement on the beach, the initial goal could not be reached because of the appearance of the unexpected low frequency signal which was initiated by the wave motion itself. However, the device and idea of this experlment were proven to be good and feasible.
Show less - Date Issued
- 1980
- PURL
- http://purl.flvc.org/fcla/dt/14021
- Subject Headings
- Bed load--Measurement
- Format
- Document (PDF)
- Title
- A TURBULENCE CURRENT METER DESIGN, CONSTRUCTION AND USE.
- Creator
- KIDERA, EDWARD HENRY, IV., Florida Atlantic University, Tennant, Jeffrey S., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The objectives of this investigation were - 1) design and build a turbulence current meter capable of measuring velocity fluctuations in a geophysical scale flow and 2) the measurement of such flow including subsequent analysis of near bottom turbulence. An unique device capable of sensing velocity fluctuations in the region 25cm above the bottom was constructed based on concepts original to the study of turbulence. A review of previous equipment and research is included for a comparison. The...
Show moreThe objectives of this investigation were - 1) design and build a turbulence current meter capable of measuring velocity fluctuations in a geophysical scale flow and 2) the measurement of such flow including subsequent analysis of near bottom turbulence. An unique device capable of sensing velocity fluctuations in the region 25cm above the bottom was constructed based on concepts original to the study of turbulence. A review of previous equipment and research is included for a comparison. The instrument's usefulness was illustrated in the open channel flow of a tidal estuary by its ability to detect the horizontal velocity field. The data obtained for the turbulence shows large variation in velocity of the lateral component on the order of 50-75% of the "mean" current speed. Digital filtering of the data reveals distinct structures of high energy, intermittent in their nature and analogous to "bursting". The energy spectrum of the longitudinal component follows the predicted slope of -1 for over two decades (.01 to 1.3 + Hz).
Show less - Date Issued
- 1978
- PURL
- http://purl.flvc.org/fcla/dt/13943
- Subject Headings
- Turbulence--Measurement, Water current meters
- Format
- Document (PDF)
- Title
- TWO DIMENSIONAL FLOW WITHIN A TRIANGULAR OSCILLATING CRACK (TURBULENCE, VORTEX STREET, TRANSITION FLOW, MIXING).
- Creator
- KIM, SOO YONG., Florida Atlantic University, Tennant, Jeffrey S., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The transition of two dimensional flow within a crack with oscillating wall is studied experimentally to establish the role of the parameters involved. Multiple instabilities in the fluid are produced by the motion of the oscillating wall. For a better understanding of the flow structure and displaying in the whole flow field at a time, flow visualization was used. Frequency, amplitude, and crack width were systematically varied. The present study shows that, in general, the frequency and...
Show moreThe transition of two dimensional flow within a crack with oscillating wall is studied experimentally to establish the role of the parameters involved. Multiple instabilities in the fluid are produced by the motion of the oscillating wall. For a better understanding of the flow structure and displaying in the whole flow field at a time, flow visualization was used. Frequency, amplitude, and crack width were systematically varied. The present study shows that, in general, the frequency and crack width play a role in the transition process at low frequencies of oscillations. However, amplitude becomes progressively important at its higher range. Results also show that the flow changes its character approximately after a Reynolds number 11420. After that the transition process continues until the Reynolds number 34322 which is the upper limit of variation of frequency (Reynolds number) in the present study.
Show less - Date Issued
- 1986
- PURL
- http://purl.flvc.org/fcla/dt/14312
- Subject Headings
- Fluid dynamics, Flow visualization
- Format
- Document (PDF)
- Title
- Investigation of carbon dioxide transport in life support helmets.
- Creator
- Camperman, John Michael., Florida Atlantic University, Tennant, Jeffrey S., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
This research explores carbon dioxide transport in life support helmet annular space using new theoretical and experimental techniques. Increased transport from next generation helmets is necessary to allow reduction of fresh gas flow and associated noise. Conventional helmet noise interferes with communications and some underwater helmets even approach hearing threshold shift levels. Helmet flow is three dimensional, unsteady, and turbulent; this research is the first known effort to...
Show moreThis research explores carbon dioxide transport in life support helmet annular space using new theoretical and experimental techniques. Increased transport from next generation helmets is necessary to allow reduction of fresh gas flow and associated noise. Conventional helmet noise interferes with communications and some underwater helmets even approach hearing threshold shift levels. Helmet flow is three dimensional, unsteady, and turbulent; this research is the first known effort to identify the fundamental mechanisms of CO2 transport. An analytical model is developed which predicts average inhaled CO2 concentration for generic helmet geometry using a mixing volume approach. The model includes sensitivity to supply flow, breath rate, metabolic CO2 production, inhalation and exhalation mixing volumes, and breathing symmetry. Numerical sensitivity analysis using the model indicates optimum design paths. Nominal head-helmet-lung geometry is identified. An experimental nominal model was developed which supports inhaled concentration measurements with air-CO2 or water-dye as working fluids. Water modeling provides flow visualization which is used to identify complex convective and turbulent CO2 transport mechanisms. Correlation of water-dye and air-CO2 results indicates conditions when molecular diffusion of CO2 is significant. The research was directed primarily toward diving helmets but is applicable to spacesuit and firefighter helmets, as well as any situation involving mass transport in a periodic mixing chamber. New analytical and experimental models are substantially more accurate than the conventional steady state helmet mixing model, and provide direction for improved helmet design.
Show less - Date Issued
- 1995
- PURL
- http://purl.flvc.org/fcla/dt/12432
- Subject Headings
- Deep diving--Equipment and supplies, Deep diving--Physiological aspects, Carbon dioxide, Underwater physiology
- Format
- Document (PDF)
