Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Publication
Articles 1 - 17 of 17
Full-Text Articles in Entire DC Network
An Investigation Of Air Side Heat Transfer Enhancement In Multi-Louver Fins Within Automotive Compact Heat Exchangers, Patrick Fix
An Investigation Of Air Side Heat Transfer Enhancement In Multi-Louver Fins Within Automotive Compact Heat Exchangers, Patrick Fix
Theses
The multi-louver fin is the primary geometric configuration used to enhance the air-side heat transfer characteristics of automotive heat exchangers today. This work presents an investigation into the effects of multi-louver fins on the air-side Stanton number (St) and Fanning friction factor (f) characteristics of a heat exchanger. Experimental St data ranging between 0.0095 and 0.065 and/ data ranging between 0.04 and 0.55 are reported for louver pitch based Reynolds numbers ranging between 30 and 4000. Brazed core test samples with multi-louver fins are utilized to complete this study. Previous investigators have correlated the air-side St and/ to geometric parameters …
Time-Frequency Distribution Analysis Of Heart Rate And Blood Velocity Variabilities In Stage 24/34 Chick Embryos, Andrew Bonacci
Time-Frequency Distribution Analysis Of Heart Rate And Blood Velocity Variabilities In Stage 24/34 Chick Embryos, Andrew Bonacci
Theses
Time-frequency distribution (TFD) analysis is a relatively new process for decomposing a complex signal to understand its spectral content Traditional signal spectral analysis examines both temporal and spectral contents distinctly. This method of analysis is suitable for signals where the spectral content is stationary and time-invariant. However, many naturally occurring signals are not only multicomponent, but are also highly time-variable, such as speech, heart rate variability, and other biological signals. Typically, the Fourier transform exposes sinusoidal frequencies present in a signal. It cannot, however, tell when these frequencies existed temporally. This is where timefrequency analysis excels over traditional spectral processing …
Heat Transfer In Microchannels, Xianming Wang
Heat Transfer In Microchannels, Xianming Wang
Doctoral Dissertations
The objective of this research was to develop an analytical solution to the heat transfer problem in microchannels with slip-flow--a heat transfer problem for gases at low pressures or in extremely small geometries, and to verify this solution experimentally. In this investigation, an analytical expression for the velocity distribution with slip-flow was obtained which involved the Knudsen (Kn) number in an infinite series form. The result showed that the velocity always increased as the Knudsen number was increased. The Knudsen number for extremely small channels may become large enough to affect significantly the velocity distribution and consequently affect the heat …
Bubble Growth Rate And Heat Transfer Suppression In The Flow Boiling Of Binary Mixtures, Taavo Raykoff
Bubble Growth Rate And Heat Transfer Suppression In The Flow Boiling Of Binary Mixtures, Taavo Raykoff
Theses
An investigation is undertaken into the nature of the bubble growth rate and heat transfer suppression in the flow boiling of binary mixtures. From an examination of the well established pool boiling theory available in the literature and a consideration of factors uniquely present in flow boiling situations, it is determined that the present pool boiling theories are roughly applicable for a finite initial interval of the bubble growth cycle during flow boiling. Furthermore, it is hypothesized that the suppression of the increase in heat transfer coefficient in binary fluids which occurs after the onset of nucleate boiling is related …
Modeling Ventricular-Vascular Coupling In The Developing Embryo, Michael Bauman
Modeling Ventricular-Vascular Coupling In The Developing Embryo, Michael Bauman
Theses
Congenital cardiovascular malformations are one of the major contributors to infant mortality in the United States today. Defects in the cardiovascular system are evident at very early stages in the developing embryo, yet there exists no substantial diagnostic tool(s) for recognizing defects at these early stages. Cardiac morphogensis occurs throughout the pre-innervated period of embryonic development. It is speculated that the flow of blood during the early embryonic stages plays an important role in the development of the cardiovascular system. Blood flow is a possible mechanism for communication between the heart and vasculature, contributing to cardiac development. The objective of …
Modeling Of Road Vehicle Lateral Dynamics, Joseph Kiefer
Modeling Of Road Vehicle Lateral Dynamics, Joseph Kiefer
Theses
The lateral dynamics of a road vehicle is studied through the development of a mathematical model. The vehicle is represented with two degrees of freedom, lateral and yaw. Equations of motion are derived for this vehicle model from basic principles of Newtonian mechanics. Both linear and non-linear models are developed. In the linear model tire lateral forces are represented by an approximate linear relationship. Transfer functions are written for the vehicle system for various control and disturbance inputs. Steady-state and transient response characteristics and frequency response are studied, and numerical simulation of the model is performed. In the non-linear model …
The Effect Of Cylindrical Obstructions On The Fluid Flow In Narrow Rectangular Channels, Gary Compagna
The Effect Of Cylindrical Obstructions On The Fluid Flow In Narrow Rectangular Channels, Gary Compagna
Theses
This thesis presents a computational fluid flow analysis in narrow rectangular channels, with regular spaced cylindrical disks acting as obstructions to fluid flow. The problem geometry is based on an approximation of the configuration used in a PCR detection chamber. Polymerase chain reaction (PCR) is a method of DNA analysis that depends on the flow uniformity within the detection channel. The nominal channel is a narrow channel with a maximum gap height of 0.13 mm and a maximum width of 5.0 mm. The fluid flow rate and channel size result in a Reynolds number less than 5. The effect of …
Cfd Analysis Of Flow Field In A Mixing Tank With And Without Baffles, Carlos Rezend
Cfd Analysis Of Flow Field In A Mixing Tank With And Without Baffles, Carlos Rezend
Theses
A computational technique has been developed to study the fluid motion in a baffled and unbaffled mixing tank. This technique was devised for a cylindrical mixing tank using a Computational Fluid Dynamics code, FIDAP. Two model analyses are presented in this thesis: Unbaffled tank steady state analysis. Baffled tank transient state analysis. The method presented in this thesis uses subroutines incorporated into the CFD program to impose the boundary conditions associated with each baffle in the tank. These boundary conditions are rebuilt for each time step to capture the effects of the relative motion between the baffles and the impeller. …
Investigation Of Nucleation And Heat Transfer During Subcooled Flow Boiling On Augmented Surfaces, Matthew Howell
Investigation Of Nucleation And Heat Transfer During Subcooled Flow Boiling On Augmented Surfaces, Matthew Howell
Theses
Heat transfer characteristics of flat augmented surfaces in subcooled flow boiling with water at atmospheric pressure were obtained as functions of the surface orientation and Reynolds number. Data was collected with the heater surface temperature between 90C and 1 15C. The maximum temperature recorded by the thermocouple closest to the heater was between 200C and 220C. Five augmented surfaces and a base line plain polished aluminum surface were prepared and their performance was experimentally obtained in a 3 mm x 40 mm rectangular channel. The five augmented surfaces consisted of a sintered plain surface, microfin #1 (fin height- .132 mm, …
A Three-Dimensional Model Of Pulsatile Flow At An Arterial Bifurcation, Andrew Hayes
A Three-Dimensional Model Of Pulsatile Flow At An Arterial Bifurcation, Andrew Hayes
Theses
Atherosclerosis in known to form at sites of predilection. These sites are typically areas of reduced pressure or shear stress. In the thesis a link between hemodynamics and atherosclerosis formation will be investigated. In the study three-dimensional pulsatile flow at a simplified carotid artery bifurcation has been modeled with computational fluid dynamics (CFD). A flow visualization experiment has also been performed on a glass replica of the bifurcation to verify the CFD results. An intense literature review has been included in the thesis to assimilate all of the published work in the area.
Validation Of The Use Of Sharc Hydrocode To Predict Explosion Effects In Vented Chambers, Gary Bush
Validation Of The Use Of Sharc Hydrocode To Predict Explosion Effects In Vented Chambers, Gary Bush
Theses
Computational Fluid Dynamics (CFD) models were created and analyzed using the commercially available hydrocode SHARC to determine if SHARC can accurately predict the behavior of explosions in enclosed vented chambers. Axisymmetric two-dimensional models were generated using the same physical parameters used in similar model tests performed by the US Army. Three different chamber/vent configurations were investigated with three charge sizes per configuration in order to compare the SHARC results to the data obtained from the model tests. The time of arrival of shocks and the peak over-pressure were compared. The calculations were then analyzed using several graphical tools currently available. …
Process Improvement To The Anodize Line Through Design Of Experiments, Shantel Gammie
Process Improvement To The Anodize Line Through Design Of Experiments, Shantel Gammie
Theses
The goal of this project is to analyze the anodize line and make process improvements which directly affect the product, the results being reduced defects, lower variability in the process and product, faster cycle time, reduced costs, and higher profits. Possible defect conditions were identified, tracked, and analyzed in order to determine the greatest problem. After recognizing a prime improvement opportunity, a design of experiments was conducted with the purpose of showing relationships between key process parameters and product characteristics. Finally, recommendations were made to raise the quality level of the anodize line, with the information that was gained throughout …
3-D Cfd Analysis Of Flow In A Mixed-Flow Pump Diffuser, Yi Zhao
3-D Cfd Analysis Of Flow In A Mixed-Flow Pump Diffuser, Yi Zhao
Theses
The primary goal of the project was to gain insight into the flow pattern in a mixed flow pump diffuser by using FLUENT CFD code and k-e turbulence model, and improve the design of a diffuser for higher pump efficiency. The diffuser chosen in this thesis is used in a mixed flow multi-stage pump which collects the nearly radial flow (water) at impeller discharge and converts it to a nearly axial flow at the inlet of the following pump stage. A three-dimensional computational model was developed for three different diffuser designs labeled as Diffuser A, Diffuser B and Diffuser C. …
Cross-Correlation: A Contrast Method For Studying Fetal Cardiovascular Time Series, Stacy Kalisz
Cross-Correlation: A Contrast Method For Studying Fetal Cardiovascular Time Series, Stacy Kalisz
Theses
Congenital cardiac malformations are a serious health concern affecting the development of the fetal cardiovascular system. Identification of a fetus with abnormalities early in pregnancy, 10-20 weeks gestation, could assist in clinical diagnosis and be a great asset in health care. This thesis is a continuation of, and works in concert with, other research efforts conducted at Rochester Institute of Technology (RIT) aimed at characterizing fetal cardiovascular health through applied signal processing. This thesis utilizes cross-correlation as a technique for analyzing the cyclic variations and assessing commonalities of individual parts of fetal umbilical artery time series data. These time series …
Conveyor Tracking Using Adept Robot With Vision Guidance System, Chen-Yu Wang
Conveyor Tracking Using Adept Robot With Vision Guidance System, Chen-Yu Wang
Theses
This thesis examines the integration of the robotic assembly workcell and the capability of the AdeptOne SCARA robot in performing both non-vision and vision based conveyor tracking. An experiment is set up for a Plastic Leadless Chip Carrier, or PLCC, chip and socket assembly operation. A PLCC chip is a square-shape integrated circuit that has its pins bent down around its perimeter to prevent damage to the pins during assembly and transportation. Binary image processing is employed by the vision system to recognize the random locations of incoming PLCC chips at the upstream location of the conveyor. When at least …
Computational Analysis Of Turbopump Diffuser In A Space Transfer Vehicle Engine With Boundary Layer Control By Suction, Yuan Xin
Theses
Future space missions by NASA that include Space Transfer Vehicles (STV) are ex pected to perform orbital transfers such as Lunar and Mars transfers and descents. STV requires deep-engine throttling thrust capability. To accomplish this, turbopumps employed in the Space Transfer Vehicles should efficiently provide a wide range of flow output. The current state-of-the-art cryogenic fuel and oxidizer turbopump designs with vaned diffusers do not perform efficiently at off-design (low) flow rate, mainly due to flow separation and stall in the vaned diffuser. This thesis evaluates the effectiveness of boundary layer control by wall suction for suppressing or eliminating the …
The Study Of Boundary Layer Control In A Turbopump Diffuser With Fluid Injection, Diego Garcia Pastor
The Study Of Boundary Layer Control In A Turbopump Diffuser With Fluid Injection, Diego Garcia Pastor
Theses
Future Space Transfer Vehicles (STV) will be required to perform missions (orbital transfer, Lunar/Mars transfer and descents) for which deep engine throttling is needed. In order to do this the turbopumps that propel the Space Transfer Vehicles need to be able to operate at different flow rates. The current state of the art cryogenic fuel and oxidizer turbopump designs do not operate well at off-design flow rates mainly due to stall and flow separation in the diffuser section. The purpose of this Thesis is to analyze the behavior of the fluid in the diffuser and the vaneless and vaned region …