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Bicycle pump

ValeryOchkov
24-Ruby II

Bicycle pump

I need not simple solution, but best solution! Слабо?

Velo-Pump.png

12 REPLIES 12

My own solution in my own Mathcad with correct temperare base unit (not kelvin but J/mol) and correct ideal gas law (not p v = R T, but p v = T)

Wath can you say about my own Mathcad?

Velo-Pump.png

Assumptions. 1. The bicycle tube does not change its volume when inflated (the tire is quite rigid). 2. The air temperature in the chamber and pump does not change.

 

Verify

Velo-man.gifPump.gif

I don't know what qualifies as the "best" solution, but here's a totally different approach.  I note that, if the temperature is assumed to be constant, the pumping must be done very slowly indeed, as my experience with pumping tyres is that the pump rapidly gets hot!

 

ValsTyre.png

Alan

 

The answer is exactly:

LucMeekes_2-1634121054377.png

which is about 91.63

 

 

Derivation:

LucMeekes_1-1634120983958.png

Success!
Luc

Nice funny story about slowly.

One filmmaker was very fond of actresses and "closely communicated" with them a lot.

This filmmaker had a heart attack and was hospitalized.

After the treatment, he set to work on the old with actresses.

One actress asked him: "Can you do THIS?"

The filmmaker replied: "I can! But slowly!"

Harassment or not harassment? It is a quastion!
If slowly - not harassment!

Here's my attempt.  I'd challenge the assumption of a toroid, but that's a detail.   The discussions about temperature are moot, imho.  You want a pressure defined while you are riding, when any pumping temperature rise has long since dissipated.  Pump it up and then check it later.  Also the thermal mass of the pump and tire >> thermal mass of air.  (and pressure recommendations already take into account any running tire heating, at least for cars)  To me the problem is a mass transfer problem.    

Answer: 31.6 strokes which seems reasonable since I've pumped up many bicycle tires.  

Edit:  Had some Z typos.

Edit 2: I just saw the target pressure was 5 atm.  So that answer is 91.796 strokes.  Which seems high, until I noticed the tire is gigantic at 110 cm diameter.  

 

DJF_0-1634152775471.png

 

 

ValeryOchkov
24-Ruby II
(To:DJF)

92! 31! Who will offer fewer pump strokes?

Sold.png

ValeryOchkov
24-Ruby II
(To:DJF)

My attempt to calculate trmperature by adiаbatic process (no loss heat)

T.png

 

Raiko
13-Aquamarine
(To:ValeryOchkov)

Here is my take

 

Bicycle pump.jpg

109!    92!   31!
Who will offer fewer pump strokes?

On more solution (Prime 6 in attach). Assumption - the air temperature in the bicycle wheel chamber has risen by 10 degrees Celsius (10 kelvin)

This answer is the most beautiful - 88 (butterfly)

2-Calc.png

With Cloud version of WaterSteanPro (www.wsp.ru) and with old Thermodynamics

Velo-Pump-WSP.png

 

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