Eph Sparrow - Academia.edu (original) (raw)

Papers by Eph Sparrow

Effect of Component Misalignment on Human Tissue Temperatures Associated With Recharging Neuromodulation Devices

Journal of Medical Devices, 2011

Numerical Heat Transfer, Part A: Applications, 2008

Numerical simulation was used to investigate natural convection in rectangular enclosures ranging... more Numerical simulation was used to investigate natural convection in rectangular enclosures ranging in aspect ratio from tall, narrow shapes to flat, wide shapes. For each of the selected aspect ratios, the Rayleigh number was varied over a range of approximately four decades. Two fundamental thermal boundary conditions were considered. One of these, commonly 15 designed as heating from below, involved the imposition of a temperature at the lower bounding wall that is higher than that at the upper bounding wall. The side walls of the enclosure were maintained adiabatic for this case. The second employed boundary condition was side walls at different uniform temperatures and adiabatic upper and lower boundaries. For each aspect ratio and for both types of boundary conditions, the onset of natural con-20 vection from the regime of pure conduction occurred at a definitive value of the Rayleigh number, termed the critical Rayleigh number. Once that threshold value was exceeded, the Nusselt number increased markedly with increasing Rayleigh number, the sharpness of the increase being greater for the bottom-heated case. For that case and for aspect ratios (height/width) greater than one, the breakdown of a flow pattern characterized by a single 25 recirculation zone caused a sudden halt to the increase of the Nusselt number. This breakdown was followed by a rapid reformation of the flow pattern into a pair of recirculation zones, one situated above the other. The critical Rayleigh number was insensitive to the aspect ratio for flat, wide enclosures but, on the contrary, the critical value increased markedly with increasing aspect ratio for tall, narrow enclosures. In general, a critical Rayleigh 30 number for the bottom-heated case exceeded that for the side-heated case by a factor of 12.

Laminar Heat Transfer in an Externally Finned Circular Tube

Journal of Heat Transfer, 1980

ABSTRACT

articles by Eph Sparrow

An experimental investigation has been carried out to determine the operating performance of a ro... more An experimental investigation has been carried out to determine the operating performance of a rotating regenerative total energy wheel (TEW). A total energy wheel is a device which conserves both sensible and latent energies. It transfers heat from a warmer to a cooler airstream while simultaneously transferring moisture from a more humid to a less humid airstream. The effectiveness of a TEW device has been measured in a special experimental facility which incorporates features that enable the obtainment of data of high accuracy. The heart of the facility is a spacious, compartmented plenum chamber made from extruded, closed-cell polystyrene which is free of extraneous heat transfer and air leakage. The plenum allows for well-defined inlet and exit conditions for the heat/moisture exchanger being evaluated. Only the plenum need be reconfigured to accommodate each heat/moisture exchanger type, a task that can be performed in a day. The remainder of the facility is universal for all heat/moisture exchangers. Most of the instrumentation is located in the universal part of the facility and is not affected by plenum reconfigurations.

inproceedings by Eph Sparrow