As the subject states I have hit a wall in a fluid mechanics associated problem in designing an experiment for my grad project.

Long story short, I'm an engineering undergrad who got a broad education in formal engineering topics (thermo, heat and mass, classical mechanics, systems, circuits, etc. etc.), but literally only did 1 fluid mechanics course. I am now a Masters student doing more biologic focused research. I am working with stem cells and I need to perform a flow experiment in which I run continuous fluid over my cells in a flow chamber at a specified flow rate.

My problem is that I have been using a syringe pump as it was what the facility provided and it's less than optimal. Only 30 mL at a time and at my specified flow rate I end up having to change it a lot and therefore flow is discontinuous and not really up to the rigor of my experiment. I get ok results, but I think it can be better.

What I'd like to do, and my problem is, that I'd like to run a circulating system with a continuous pump. I just don't know how to figure out what pump to use. I have some support and money from the lab, and I'd prefer to be able to tweak the flow rate if possible.

To set up the problem:

I am using an Ibidi mu VI 0.4 chamber slide. Full literature available here:


Quick and dirty dimensions:

Outer dimensions (w x l) 75.5 x 25.5 mm² Adapters Female Luer Number of channels 6 Channel volume 30 µl Channel height 0.4 mm Channel length 17 mm Channel width 3.8 mm Volume per reservoir 60 µl

Using their literature provided I have already calculated that I need to provide a flow rate of:

4.73 mL/min

which corresponds to a shear stress of: 6 dyne/cm^2 (0.6 Pa)

my tubing dimensions are:

L = 20 cm inner d = 1.6 mm

I have a reservoir of cell media of maximum 50 mL which needs to sit beside the microscope in a heater to provide the maximum "comfort" and conditions that my cells like (37 degrees C)

Now, for the life of me I can't figure out how to determine an appropriate set up/pump to make this into a continuous flow, needed to pump/circulate for 2 hours

Can anybody at least put me on the right path to designing this?? I don't have the time to relearn all my fluids, but I don't mind brushing up on topical required reading to solve.

I can also attempt to make a diagram if you need a better visual representation. I hope I explained my problem thoroughly though.

Thank you,

A frustrated grad student

  • $\begingroup$ You should check out a peristaltic pump and consider an accumulator if you want to reduce pulsing. $\endgroup$ – Solar Mike Jul 23 '19 at 19:55
  • $\begingroup$ Ok, I'm going to look into that. Busy scouring literature and different pumps now. Thanks for at least giving me an avenue to look into. $\endgroup$ – BMEGrad2020 Jul 23 '19 at 19:57
  • $\begingroup$ What you want is a "positive displacement" pump that will deliver a given flow rate at whatever pressure is needed (within reason) to send it through the plumbing. Peristaltic pumps are one type, and probably a good choice, since they are easy to clean/sterilize and self priming. $\endgroup$ – alephzero Jul 23 '19 at 20:26
  • $\begingroup$ see my answer on the physics stack exchange. -Niels $\endgroup$ – niels nielsen Jul 24 '19 at 0:31
  • 1
    $\begingroup$ Now surfaces the issue of duplicate posts: see answer here : physics.stackexchange.com/a/493247/207455 $\endgroup$ – Solar Mike Jul 24 '19 at 4:07

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