I'm trying to calculate the compression stress on the fuel cell components so that I can determine the porosity of the diffusion media as in the following paper:
R. W. Atkinson, Y. Garsany, B. D. Gould, K. E. Swider-Lyons, I. V Zenyuk, ACS Appl. Energy Mater. 1, 191–201 (2018).
However, I only know the torque that I apply to the eight bolts holding the cell together - 65 lb in. How can I convert this to a pressure on the components?
Hello, thanks for putting out this question. I too have been investigating the same for a while now. As far as our finding goes so far, we could understand that compression can be explained in two ways: (1) overall compression of the cell assembly induced by the applied torque on the bolts and (2) local compression on the GDL and the catalyst layer.
For the first, we could simply employ the relation of 'Kellerman & Klein’ model "Tapplied = K x F Total" where, T applied: Torque in Nm, F total: Clamping force in N and K factor given by K= (p/2*pie) + (0.583 x d x Kf) + (D x Kh). Here, p: thread of screw, d: effective dia of screw, kf: friction factor of filets in screw, kh: friction factor under head of screw on washer and D: Dia of screw head. This lead to giving you the overall assembly pressure in the fuel cell system.
However, for local compression on the GDL and the CL, the situation is far more complex, and difficult to estimate. Some modelling and simulation based studies have showed a homogeneous pressure distribution based on applied torque, on the gasket and GDL (1-2.5 MPa) apprx. (Now this would again strictly depend on the mechanical properties of GDL and gasket you choose)
In addition you can refer to this article:
Article On the Compressibility of Gas Diffusion Layers in Proton Exc...
Thanks, and please do let us know your findings and suggestion if any.
Regards
Mainak
Alex Gupta , Please do share your findings/observations/comments on the same.
Thanks and regards
Mainak
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