[Woopy]

(135) 1. Liquid hydrazine (N2H4) is injected into a jet combustion chamber at 400 K and burned with 100 % excess air that enters at 700 K. The combustion chamber is jacketed with water. The combustion products leave the jet exhaust at 900 K. In the test, 50 kmol of hydrazine are burned per hour. Water at 25 °C enters the water jacket for cooling at a mass flow rate of 40 kg/min. The reaction is

N2H4(l) + O2(g) ---> N2(g) + H2O(g)

Data: of N2H4(l) = 44.77 kJ/gmol; of N2H4(l) = 139 J/gmol°C

(95) a. What is the volumetric flow rate of water out of the cooling jacket (at 1 atm)?

(20) b. The diameter for the water jacket inlet is 0.1 m, and the diameter for the jacket outlet is 0.03 m. The water jacket outlet is 2 m below the jacket inlet. Are the kinetic and potential energy changes for the water significant?

(20) c. If the water flow were halted, what would be the temperature of the outlet gas from the reactor? The reactor is made of nickel, which melts at 1453 °C. Is this a problem? What design features should the reactor have to mitigate the effects of this possible accident?





For this problem, it seems like not enough information is given. I should be given the molar heat capacity of water, nitrogen, and oxygen.

What I want to do for this is to basically bring the reactants down to 298 K using heat capacity, then react it at 298 with the standard heat of reaction, then bring it back up to 900 K with heat capacity to get the enthalpy change of the reaction.

Once I know that, I might have a chance at finding the temperature of the water leaving the jacket, but from there I don't know how I will find the density as a function of temperature to get the volumetric flow rate.