Insights Blog
-- Browse All Articles --
Physics Articles
Physics Tutorials
Physics Guides
Physics FAQ
Math Articles
Math Tutorials
Math Guides
Math FAQ
Education Articles
Education Guides
Bio/Chem Articles
Technology Guides
Computer Science Tutorials
Forums
General Engineering
Mechanical Engineering
Electrical Engineering
Aerospace Engineering
Nuclear Engineering
Materials Engineering
Trending
Featured Threads
Log in
Register
What's new
Search
Search
Search titles only
By:
General Engineering
Mechanical Engineering
Electrical Engineering
Aerospace Engineering
Nuclear Engineering
Materials Engineering
Menu
Log in
Register
Navigation
More options
Contact us
Close Menu
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Forums
Engineering
Mechanical Engineering
How does stacking and creating an air gap affect fabric air permeability?
Reply to thread
Message
[QUOTE="256bits, post: 5885612, member: 328943"] Δ Here is how I am thinking about it. A tube with 2 barriers, 1 and 2, sufficiently far enough apart forming a chamber and with an orifice in each barrier. P, ρ, T, v(velocity) are the bulk conditions of the fluid on the pressurized side. Similarly, we have conditions within the chamber, and on the atmospheric side. Need Q. Incompressible: Case 1: Simplest case: well mixed chamber v = v[SUB]c[/SUB] = v[SUB]atm[/SUB] for continuity. Same for ρ and T. P[SUB]c[/SUB] = ({P+P[SUB]atm[/SUB])/2 Half of what it is with one barrier. Difference in pressure determines the flow across the orifices. Assume linear relationship of P and Q through an orifice. ( Is that true ? ) Thus, Q with 2 barriers is half that with one barrier. Case 2: NOT well mixed. Here the barriers are brought closer together, so that the velocity of the fluid leaving barrier 1 impacts upon the orifice in barrier 2. Does it matter if the orifices are in line, or not. As a result, is this Q less than, the same, or greater than that of case 1. Perhaps try something Bernoulli, or more advanced if need be. Compressible: The density of the fluid should decrease as it moves from higher pressures to lower through the barriers. We should use mass flow rate, mdot, since volumetric flow rates are unequal on either side of the orifice. Let's see, high pressure, high density mdot expands through an orifice into the chamber. Same mdot at lower density and larger volume has to exit the chamber to the low pressure side, needing either a larger second orifice or a larger pressure within the chamber through a same size orifice. So the chamber should with same size orifices be above the average pressure between high and low sides. Moving the barriers closer together, we meet the same situations of unmixed flow and orifice1 velocity impacting upon orifice 2. For multiple orifices on each barrier, things should be similar to single orifices. Considerations: 1. Does Q or mdot through an orifice follow a linear relationship with ΔP across the orifice. 2. How much change in density would there be for air at moderate pressures. 3. Using the incompressible flow analysis, how much error does that give to an actual measured real flow. 3. Is an orifice model sufficient or the correct model to use. Sorry if I can't give a definitive answer for stacked filters, but at least you have something to think about and research. Any errors in the modelling, please feel and obligated to correct as you wish. DU [/QUOTE]
Insert quotes…
Post reply
Forums
Engineering
Mechanical Engineering
How does stacking and creating an air gap affect fabric air permeability?
Back
Top