Fluid Flow - Heat Transfer

Definitely under Construction

Entry point to the full-text publications of NASA's "Thermal Energy Conversion at NASA Glenn Research Center"
FY 2012 publications : nothing of interest for fluid flow/heat transfer
FY 2011 publications : nothing of interest for fluid flow/heat transfer
FY 2010 publications : nothing of interest for fluid flow/heat transfer
FY 2009 publications : nothing of interest for fluid flow/heat transfer
FY 2008 publications : nothing of interest for fluid flow/heat transfer
FY 2007 publications : nothing of interest for fluid flow/heat transfer
FY 2006 publications : nothing of interest for fluid flow/heat transfer
FY 2005 publications : nothing of interest for fluid flow/heat transfer
No prior publications avialable at this site.
Sage is a dedicated thermodynamic code for modeling Stirling-cycle based machines, developed by Gedeon Associates of Athens, OH (Gedeon, 1995). Oscillatory flow and heat transfer in a Stirling Engine Regenerator by Yuan,Zheng Shan, PhD Thesis at Case Western Reserve Univeristy, 1993 myCopy to be studied. Obtained via http://www.libraries.psu.edu/psul/montalto.html
[1] UPDATE ON THE EVALUATION OF DIFFERENT CORRELATIONS FOR THE FLOW FRICTION FACTOR AND HEAT TRANSFER OF STIRLING ENGINE REGENERATORS, Bernd Thomas, Deborah Pittman, 2000, AIAA-2000-2812
Re-evaluates the experimental data obtained at the Oscillating-Flow Regenerator Test Rig. Experimental data from Tong/London, Blass, Miyabe etal, Tanaka, et.al., ILK Dresden and Kuehl plus data presented by Gedeon and Wood. Parameters varied are Reynolds number, Valensi number, flush ratio, wire diameter, mesh width and porosity, and gas type ( air and He ), see their Table 1. This table also includes the equations they think are most relevant. For example for a regenerator which uses wire screens as the matrix :

L       = length of regenerator volume
d       = wire diameter
rho     = density of working fluid
nue     = kinematic viscosity of working fluid
epsilon = porosity = 1 - Vmaterial/Vtot
unod    = empty tube velocity  
u       = unod /epsilon

                   L*(1-epsilon)   rho
pressure drop = cF*------------- * --- * u
                      d*epsilon     2

with friction coefficient cF = 129/Re + 2.91/Re^0.103

                     d*epsilon*u
and Re-number : Re = ---------------
                     (1-epsilon)*nue

Similar equations are given for heat transfer and for metal felts.
The experiments by Gedeon and Wood (which are the main topic of this paper) are described as :
"The Oscillating-Flow Regenerator Test Rig was specially designed to analyze regenerator pressure chop and heat transfer for oscillating flow. For that purpose a motor-driven piston-cylinder assembly was installed to push gas back and forth through the regenerator sample. The friction factor was calculated fiom the piston pV-power, which was measured directly. To measure heat transfer, the regenerator sample was inserted between a heater and cooler in order to imposes an axial temperature gradient along the regenerator." Reynolds numbers are always below 3400 = laminar flow limit ? Is that the reason while the equaions don't show any dependency on Valensi number ?
As these equations give only averages over a complete oscillation they are useful in estimating energy losses and heat transfer performance once an ideal adiabatic analysis has been conducted.
Oscillatory Flow and Thermal Field Measurements at the Interface between a Heat Exchanger and a Regenerator of a Stirling Engine, Niu & Simon & lbrahim & Gedeon, 2002 37th Intersociety Energy Conversion Engineering Conference (IECEC)
This is an interim report representing the experimental facility together with some preliminary instantaneous velocity and temperature data. Reynolds number of 20700 (the length scale is the cooler tube diameter and the velocity scale is the cycle maximum bulk mean velocity in the cooler tubes).Valensi number of 14.3 (VA=ω*d^2/(4*nue) ; ω=2*πF ; d = cooler tube inner diameter
Because of its interim nature data valuable for the construction of cooler/regenerator/heater are not available. Not that this research is conducted under the "US. Department of Energy Office of Energy Efficiency and Renewable Energy under the Advancement of Solar DishIConverter Technology Initiative".
Nice entry into that program, worthwhile to read again to look at some of their references.


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Last revised: 01/10/15