Throttling Process

dear all

What is the throttling Process?
what is Joule homson Effect?

A throttling process is a process that is isenthalpic. Thus, $$h_1 = h_2$$. This means that the following is also true, $$u_1 + P_1 v_1 = u_2 + P_2 v_2$$. So if you drop pressure in a throttling value, you increase the internal energy, and vise versa.

The Joule -thomson- effect deals with the fact that as you expand a gas it looses temperature. Note that for hydrogen; however, it gains temperaturee as it expands. This makes hyrdogen particularly dagnerous.

Pressure drops in CNG kit Pressure regulator from 300 bar to 4 bar in 1st chamber due to expansion is it throttling process? temperature also drops in it.

Yes, that is exactly what it is.

Edit: wait, what do you mean by expansion? Is it going through a nozzle?

no it is going throug valve (sloninoid valve) from storage cylinder through high pressure pipe into solinoid valve and then in the 1st stage chamber of pressure regulator.

Yes, it is a throttling valve.

what is the value of joule-thomson coefficient for methane