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Showing papers by "Ephraim M Sparrow published in 2016"




Journal ArticleDOI
TL;DR: In this paper, the authors investigated the thermal and fluid flow design of a double-pipe heat exchanger in which the wall of the inner pipe is helically corrugated.

38 citations


Journal ArticleDOI
TL;DR: It is hoped that this catalogue of burn predictions for various beverage volumes, beverage service temperatures, and durations between beverage service and spill can be used by both beverage industries and consumers to reduce the threat of burn injuries.
Abstract: A comprehensive study was performed to quantify the risk of burns from hot beverage spills. The study was comprised of three parts. First, experiments were carried out to measure the cooling rates of beverages in a room-temperature environment by natural convection and thermal radiation. The experiments accounted for different beverage volumes, initial temperatures, cooling period between the time of service and the spill, the material which comprised the cup, the presence or absence of a cap and the presence or absence of an insulating corrugated paper sleeve. Among this list, the parameters which most influenced the temperature variation was the presence or absence of a cover or cap, the volume of the beverage and the duration of the cooling period. The second step was a series of experiments that provided temperatures at the surface of skin or skin surrogate after a spill. The experiments incorporated a single layer of cotton clothing and the exposure duration was 30 s. The outcomes of the expe...

31 citations


Journal ArticleDOI
TL;DR: In this paper, five widely recognized turbulence models were evaluated using experimental results, including RANS-based two-equivalent models, and three RANSbased three-quadratic models.
Abstract: Turbulent fluid flows with a swirl occur in numerous engineering practice situations. Five widely recognized turbulence models were evaluated using experimental results. Among the RANS-based two-eq...

28 citations


Journal ArticleDOI
TL;DR: In this article, the upper bound of the Nusselt-Reynolds correlation was shown to increase with the number of angles and chamfers, and the results were extended to other fluids by using the ratio of Prandtl numbers.

17 citations


Journal ArticleDOI
TL;DR: In this article, a rotating fan simulation, which takes full account of the rotation of the fan blades and of the true nature of the delivered flow, was implemented with high fidelity.

11 citations


Journal ArticleDOI
TL;DR: Both the tissue temperature results and the thermal damage metrics found no evidence of tissue injury when time-varying preprogrammed protocols are used in the recharging of neuromodulation implant-encased batteries.
Abstract: This project was intended to determine whether the preprogrammed time-varying recharge protocol for a battery incased in a neuromodulation implant can give rise to tissue temperatures that surpass a safe level or are otherwise benign. The study included the development of a highly accurate model of all the thermal processes that are activated by the recharging of the battery contained within the neuromodulation implant. The model was implemented by numerical simulations performed for several realistic operating conditions. The computed spatial and temporal tissue temperature distributions were employed to estimate possible tissue damage by making use of two independent methodologies. Independent calorimeter-based experiments were performed to provide validation for the calculated rates of heat generation in the coils of the implant. Spatial and temporal tissue temperature distributions extracted from the numerical simulations revealed the thermal effects associated with several realistic operating protocols. None of the operating protocols gave rise to temperatures above 42℃. Numerical values of thermal tissue damage metrics were determined and compared with accepted values which correspond to the absence and the presence of tissue damage. The experimentally determined rate of heat generation in the implant coils validated that from electrical measurements to within 2%. Both the tissue temperature results and the thermal damage metrics found no evidence of tissue injury when time-varying preprogrammed protocols are used in the recharging of neuromodulation implant-encased batteries.

6 citations


Book ChapterDOI
19 Apr 2016

5 citations


Journal ArticleDOI
TL;DR: In this article, it was found that the complexity of the fluid flow delivered by the rotating fan gives rise to a large fluid resistance within the pin-fin array, such that the delivered air flow rate was only about 37% of that for the P-Q case.
Abstract: A heat exchanger and the fluid mover that delivers a working fluid to the exchanger inlet may experience profound interactions, which argues against treating them as separate entities. On the other hand, the design practice commonly assumes that the fluid delivered to the heat exchanger inlet is specifiable without consideration of any possible influence of the exchanger. The magnitude of the flow rate arriving at the exchanger inlet is generally based on the pressure rise—flow rate (P-Q) curve supplied by the manufacturer of the fan and coupled with the assumption that that flow is uniformly distributed across the exchanger inlet. It was found that the complexity of the fluid flow delivered by the rotating fan gives rise to a large fluid resistance within the pin-fin array, such that the delivered air flow rate was only about 37% of that for the P-Q case. On the other hand, the corresponding reduction in the rate of heat transfer was, at most, 27%.

5 citations


Journal ArticleDOI
TL;DR: In this article, the thermal conductivities of reclaimed asphalt pavement (RAP) and its components have been investigated using finite-element techniques, which can be effectively used for modelling asphalt mixing drums in order to optimize the relative proportions of new and recycled materials and to determine the amount of time required to achieve full melting inside of the drum.
Abstract: Up to the present, most work on the use of reclaimed asphalt pavement (RAP) has been empirical in nature. Very recent advances have demonstrated that finite-element techniques can be effectively used for modelling asphalt mixing drums in order to optimise the relative proportions of new and recycled materials and to determine the amount of time required to achieve full melting inside of the drum. A necessary prerequisite for the modelling is a definitive knowledge of the thermal conductivities of RAP and its components. This need motivated the present experimental work which encompassed RAP particles, RAP particles with the asphalt binder removed, and pure asphalt binder of different degrees of ageing. Also evaluated were taconite tailings, residual rock from the processing of iron-containing ore, and sand. The tailings have been mentioned as a candidate aggregate. The conductivity results for the solid media were related to three metrics: (a) the size ranges of the solids, (b) the density of the sample a...



Journal ArticleDOI
TL;DR: In this paper, a noninvasive means of determining body core temperature is proposed and characterized by synergistic use of numerical and experimental simulations, which is demonstrated that the new surface probe yields skin surface temperature measurements that are within a few tenths of a degree of the body's core temperature.
Abstract: A highly accurate noninvasive means of determining body core temperature is proposed and characterized by synergistic use of numerical and experimental simulations. It was demonstrated that the new surface probe yields skin surface temperature measurements that are within a few tenths of a degree of the body core temperature. Advanced simulation techniques such as the Monte Carlo method for the determination of radiant heat losses were used to ensure high accuracy. Convective heat losses were also accounted. Full account was taken of the multilayer nature of the tissue bed beneath the skin surface, each layer with its specific thermophysical properties, blood perfusion, and metabolic heating. For the validation of the numerical simulation model, an experimental apparatus was fabricated and operated. The experimental data supported the numerical predictions. The capability of the probe to accurately follow thermal transients was the focus of a redesign, yielding small-fraction-of-a-minute following...