Hi,
I have been tasked with proving that it is safe to handle off the road tyres fitted to haul trucks while still inflated to 5PSI (the procedure wants us to go to 0 PSI but this causes the tyre to slip from the rim and damage valves). However, i can only find calculations for explosions that involve some form of combustible material rather than just a sudden release of compressed gas.
The tyre has a volume of 4.8 m^3 and the pressure is 5 PSI, i did find this equation:
w = ((p1 v1)/(k-1))(1-(p1/p2)^((1-k)/k))
which gives an energy of 130 kJ at 5 PSI (equivalent to 30g of TNT)
however, this seems a little low and i ran the calcs again for operating pressure (100PSI) which gave a value of 4.2 mJ (equivalent to .93kg of TNT) which also seems very low, which is largely anecdotal comparing videos of exploding tyres vs even 2 kg of TNT but this may be due to the shaped nature of the explosion on a tyre (the lock rings usually fail so the energy is forced out the circumference of the rim).
If anyone can verify that this is the correct formula or suggest your own or even provide a range where energy releases start to become dangerous ie. above 200 kJ at 2m it will shatter windows or something along those lines.
Thanks,
Joe
I have been tasked with proving that it is safe to handle off the road tyres fitted to haul trucks while still inflated to 5PSI (the procedure wants us to go to 0 PSI but this causes the tyre to slip from the rim and damage valves). However, i can only find calculations for explosions that involve some form of combustible material rather than just a sudden release of compressed gas.
The tyre has a volume of 4.8 m^3 and the pressure is 5 PSI, i did find this equation:
w = ((p1 v1)/(k-1))(1-(p1/p2)^((1-k)/k))
which gives an energy of 130 kJ at 5 PSI (equivalent to 30g of TNT)
however, this seems a little low and i ran the calcs again for operating pressure (100PSI) which gave a value of 4.2 mJ (equivalent to .93kg of TNT) which also seems very low, which is largely anecdotal comparing videos of exploding tyres vs even 2 kg of TNT but this may be due to the shaped nature of the explosion on a tyre (the lock rings usually fail so the energy is forced out the circumference of the rim).
If anyone can verify that this is the correct formula or suggest your own or even provide a range where energy releases start to become dangerous ie. above 200 kJ at 2m it will shatter windows or something along those lines.
Thanks,
Joe
