The Souders–Brown equation has been a tool for obtaining the maximum allowable vapor velocity in vapor–liquid separation vessels 
Category: Thermodynamics Calculator
This category helps you to calculate the basic thermodynamics numerical related to pressure, entropy, efficiency etc., – WINGS OF AERO
It states that the flow of fluid is related to a number of factors the viscosity of the fluid, the pressure gradient across the tubing and the length and diameter of the tubing
Thermal Velocity is a typical velocity of a thermal motion of particles to make up a gas
Isentropic relation between temperature and density 
(Wikipedia)
Isentropic process: It is the process in which the entropy remains constant and heat and mass transfer does not take place. It is also called as the reversible adiabatic process.
Using the above formula, the value of temperature T2 can be calculated
Isentropic relation between density and pressure
(Wikipedia)
Isentropic process: It is a process in which the entropy remains constant and heat and mass transfer does not take place. It is also called as the reversible adiabatic process.
Using the above formula, the value of density rho2 can be calculated.