A Transient Model of Induced Natural Circulation Thermal Cycling for Hydrogen Isotope Separation Page: 3 of 10
View a full description of this article.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
WSRC-MS-2005-00145
Two loop configurations were considered, one with a vertically oriented finned coil and one with a
horizontal finned coil. Figure 1 shows schematics of the two configurations. There are two loops in the
system, hot and cold, which alternately circulate nitrogen to heat or cool the packed bed. Each loop has a
butterfly valve. The valve in the circulating loop is open and the valve in the idle loop is closed. These
valves open and shut when the packed bed in the coil reaches the high and low temperature limits,
switching operation from one loop to the other. The section with the packed bed is common to both loops.
There is an electrical heater and a liquid nitrogen cooler in each loop to induce circulation. The flow is
clockwise in both loops of the device with the vertically oriented finned coil and counter-clockwise in the
device with the horizontally oriented finned coil.Liquid N2
Cooler
Finned Cold Butterfly Valve
Coil with Loop
Ceramic
Beads
Electrical Liquid N2
Heater Cooler
Hot LiquidN
Butterfly Valve Loop Cooler
Electrical
Heater
Vertical ConfigurationLiquid N2
Cooler
Finned Coil
with Ceramic
Beads
Cold Loop Electrical
Heater
Hot Loop
Electrical
Heater
Horizontal ConfigurationFig. 1: Schematics of the two configurations of the double thermosyphon modelled.
Model Description
The hot and cold loops are modelled separately with one-dimensional momentum and thermal energy
equations. The thermal inertia of the solid structures in the loops significantly impacts the heat-up and
cool-down rates of the circulating nitrogen gas and therefore the packed bed. The solid structures in the
sections are modelled with separate thermal energy equations, which are coupled to the fluid thermal
energy equations through convection heat transfer. The boundary conditions for each loop are the specified
surface temperature of the liquid nitrogen cooler and the electrical heater power.
The model alternately simulates circulation in the hot and cold loops. Flow in the hot loop is simulated
until the packed bed reaches the upper temperature limit, at which time the model starts to simulate flow in
the cold loop. The cold loop flow is simulated until the packed bed reaches the lower temperature limit,
Upcoming Pages
Here’s what’s next.
Search Inside
This article can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Article.
Shadday, Martin A., Jr. & Heung, Leung Kit. A Transient Model of Induced Natural Circulation Thermal Cycling for Hydrogen Isotope Separation, article, July 12, 2005; [Aiken, South Carolina]. (https://digital.library.unt.edu/ark:/67531/metadc881900/m1/3/: accessed July 16, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.