scispace - formally typeset
Search or ask a question

Showing papers by "Ephraim M Sparrow published in 2012"


BookDOI
04 Dec 2012
TL;DR: In this paper, the role of Nanoparticle suspensions in Thermo/Fluid and Biomedical Applications is discussed. But the authors do not discuss the application of nanoparticles in medical applications.
Abstract: Review of Nanofluid Applications Kaufui V. Wong and Omar De Leon The Role of Nanoparticle Suspensions in Thermo/Fluid and Biomedical Applications Khalil M. Khanafer and Kambiz Vafai Multiscale Simulation of Nanoparticle Transport in Deformable Tissue during an Infusion Process in Hyperthermia Treatments of Cancers Ronghui Ma, Di Su, and Liang Zhu Superparamagnetic Iron Oxide Nanoparticle Heating: A Basic Tutorial Michael L. Etheridge, Navid Manuchehrabadi, Rhonda R. Franklin, and John C. Bischof Light-Induced Energy Conversion in Liquid Nanoparticle Suspensions Patrick E. Phelan, Robert Taylor, Ronald J. Adrian, Ravi S. Prasher, and Todd P. Otanicar Radiative Properties of Micro/Nanoscale Particles in Dispersions for Photothermal Energy Conversion Qunzhi Zhu and Zhuomin M. Zhang On the Thermophysical Properties of Suspensions of Highly Anisotropic Nanoparticles with and without Field-Induced Microstructure Jerry W. Shan, Anna S. Cherkasova, Chen Lin, and Corinne S. Baresich Advances in Fluid Dynamic Modeling of Microfiltration Processes John E. Wentz, Richard E. DeVor, and Shiv G. Kapoor Computational Analysis of Enhanced Cooling Performance and Pressure Drop for Nanofluid Flow in Microchannels Clement Kleinstreuer, Jie Li, and Yu Feng Natural Convection in Nanofluids Massimo Corcione Index

156 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present a historical perspective on the Savonius turbines and discuss recent developments in analysis methods which intend to optimize the turbines for powering cellular communication towers in developing parts of the world.
Abstract: Wind turbine use is expanding throughout the world as a means to provide electricity without contributing to the increase in global-warming gases. Most commonly, very large, horizontal-axis turbines are constructed in fleets that are connected to national-level electrical grid systems. More recently, there has been a desire for more local, small-scale power production that can be used to power very specific pieces of equipment or buildings. Some of the small-scale turbines are designed differently from their larger counterparts—they are driven by drag forces rather than by lift. Drag-driven turbines are typically called Savonius turbines. This paper, which presents a historical perspective on Savonius turbines, will illustrate their potential for providing local power. Finally, we will discuss recent developments in analysis methods which intend to optimize Savonius turbines for powering cellular communication towers in developing parts of the world.

82 citations


Journal ArticleDOI
TL;DR: In this article, a CFD approach has been taken which provides drag coefficients that are used to predict depths independent of a fall-rate equation (FRE), which is known that FRE depths are reasonably accurate for ocean environments that match the experiments from which the correlations were developed.
Abstract: Computational fluid dynamic techniques have been applied to the determination of drag on oceanographic devices (expendable bathythermographs). Such devices, which are used to monitor changes in ocean heat content, provide information that is dependent on their drag coefficient. Inaccuracies in drag calculations can impact the estimation of ocean heating associated with global warming. Traditionally, ocean-heating information was based on experimental correlations which related the depth of the device to the fall time. The relation of time-depth is provided by a fall-rate equation (FRE). It is known that FRE depths are reasonably accurate for ocean environments that match the experiments from which the correlations were developed. For other situations, use of the FRE may lead to depth errors that preclude XBTs as accurate oceanographic devices. Here, a CFD approach has been taken which provides drag coefficients that are used to predict depths independent of an FRE.

22 citations


Journal ArticleDOI
TL;DR: In this paper, a dynamic model and drag coefficient calculations of a temperature probe descent into ocean water are presented to predict the depth of the probe during descent into the ocean during a measurement of ocean temperatures.
Abstract: Computational fluid dynamics techniques have been applied to model fluid flow in the vicinity of oceanographic temperature probes A major goal of the modeling effort is the determination of drag coefficients for probe descent into ocean water These drag coefficients can be used, in conjunction with a dynamic model of the probe, to predict the depth of the probe during descent Accurate depth information is essential for the proper measurement of ocean temperatures and, consequently, ocean heating associated with climate change Until recently, probe depths were predicted with the use of experimental calibrations which relate time-of-flight and depth Those calibrations are limited in their accuracy, they are confined to conditions that match the experiments from which the calibrations were determined, and they are unable to account for variations in quantities such as the drop height or initial probe mass The dynamic model and drag coefficient calculations presented here are, to the best knowledge of t

20 citations


Journal ArticleDOI
TL;DR: In this paper, the authors used numerical simulation to increase the knowledge base for failure of instrumentation or control cables utilized in the nuclear power industry subjected to an industrial fire, and found that the time to failure is well correlated with the thermal mass per unit length of the cable.

10 citations


Journal ArticleDOI
TL;DR: In this paper, two novel methods for the measurement of the thermal conductivity of solids are described, one for high-conductivity media (all metals), while the second is appropriate for media of low conductivity (as low as that of air).

8 citations


Journal ArticleDOI
TL;DR: In this article, the authors considered duct flows in which the fluid encounters a patterned array of structures along its path of flow and found that the porous medium model is a viable approach, thereby adding support to current heat and fluid flow models of heat exchangers.
Abstract: This article is concerned with duct flows in which the fluid encounters a patterned array of structures along its path of flow. A heat-exchanger tube bank is an example of a patterned array of structures, whose deployment repeats periodically in the flow direction. There are three issues to be highlighted here. The first relates to the model used in standard commercial software that deals with periodic structures. That model envisions the periodic structure to be a porous medium. This approach is also used in the analysis of heat-exchanger performance.The second issue concerns the nature of the flow that follows the breakdown of the friction-dominated laminar regime. The third focus is the identification of the location of the maximum velocity within the periodic structure. It was found that the porous-medium model is a viable approach, thereby adding support to current heat and fluid-flow models of heat exchangers. The nature of the flow following the breakdown of the friction-dominated laminar regime is...

7 citations


Proceedings ArticleDOI
23 Jul 2012
TL;DR: In this paper, the authors presented a working prototype for a vertical-axis wind turbine that is capable of powering cellular communication equipment, which is designed to be affixed to already existing communication towers and thereby has a reduced cost of installation.
Abstract: A multi-year research program has generated a working prototype for a vertical-axis wind turbine that is capable of powering cellular communication equipment. The turbine is designed to be affixed to already existing communication towers and thereby has a reduced cost of installation. The turbine is driven by air drag forces rather than by lift. It has a number of novel features including venting slots that are created to reduce the thrust loading on the communication tower. In addition, contoured caps are affixed to the upper and lower edges of the turbine blades to increase power production. As previously mentioned, the turbine design itself is a drag-based concept rather than the more typical lift-driven devices. The advantages of the drag-based design are: 1. lower startup wind speed, 2. slower rotation and a lessened vibrational load on the tower, 3. less sensitive to wind direction, and 4. it can be aligned with the tower.The design of the device was carried out through a combination of numerical simulation and experimentation. The simulations have evolved from preliminary two-dimensional calculations to a fully three dimensional, unsteady, computational fluid dynamic analysis. Simultaneously, the experiments have included both in-field and wind-tunnel tests of various stages of the turbine design.An outcome of the effort is a third-generation working vertical-axis wind turbine (VAWT) that is currently being evaluated with in-field tests. The results of the tests are positive and confirm the expectations that were developed during the product design phase. The turbine, which can be constructed with various rotor stages, has the capability of producing approximately 2–3 kW of power in wind-speed environments of 12–16 m/s. These power production levels are greatly in excess of that required to fully power the electronics equipment on a typical cellular communication tower. Unfortunately, subsequent tests showed that the turbine production dropped approximately sevenfold. The cause of the decrease in performance was friction in the mechanical components which coupled the rotating shaft to the support structure. This recognition reinforces the importance of low-resistance mechanical design for VAWTs.Another aspect of the turbine design is the specialized electronics which allow the electronics to adapt to local wind speeds and consequently increase the efficiency of the power production.Copyright © 2012 by ASME

1 citations