Pressure Reservoir Calculations

Problem Statement

Description

The Liquid Propellant Engine Test Stand (LiqPETS) will initially use a blowdown high pressure feed system to supply Liquid Engine 0 (LE-0 or "LEO") with Liquid Oxygen (LOX) and Isopropyl Alcohol (IPA). The goal of this calculation is to determine how many nitrogen tanks are required to supply the test stand with enough pressurant to perform a static-fire (hot fire) of the engine.

Given

LEO is expected to consume:

$1.13\frac{lbm}{s}$ of LOX
$0.94\frac{lbm}{s}$ of IPA.

The total volume of the propellant tanks is $4.0gal$ each.

The pressure supplied to the LOX side must not be more than $500PSI$

The pressure supplied to the IPA tank must not be more than $800PSI$

The stand will use standard $300{ft}^3$ $2000PSI$ K-type pressure vessels

Find

[_] The pressure losses from the pressure reservoir to the tanks

[X] The volume of nitrogen required to maintain driving pressures in both propellant tanks

[X] The number of nitrogen bottles required to achieve this

Solution

Volume and Tank Quantity

Determine the volume of the K-bottle $$\frac{P_1}{P_2} = \frac{\nu_2}{\nu_1}$$



In [3]:

    
import numpy
from matplotlib import pyplot as plt



In [4]:

    
# Volume of gas in the bottle
volume_gas = 43.61 #L

# Pressure of the gas in the bottle standard
pressure_gas = 2000 #PSI

# convert to metric
volume_gas = volume_gas * 0.001 # L/m3
pressure_gas = pressure_gas * 6.89476 #kPa/PSI

print("initial gas pressure: " + str(pressure_gas))
print("initial gas volume: " + str(volume_gas))

# Volume of propellant tanks
volume_tanks = 8.0 #gal
volume_tanks = volume_tanks / 264.172 # m3 / gal

# initial and final volumes
quantity_cylinders = numpy.arange(0,10,1)
quantity_runs = 3
volume_initial = volume_gas * quantity_cylinders
volume_final = volume_initial + volume_tanks * quantity_runs

# initial and final pressures
pressure_initial = pressure_gas # kPa
pressure_final = pressure_initial * (volume_initial / volume_final)

# return to imperial unitz
pressure_final = pressure_final / 6.89476

plt.plot(quantity_cylinders, pressure_final)









    



initial gas pressure: 13789.52
initial gas volume: 0.04361






    Out[4]:





[<matplotlib.lines.Line2D at 0x7fb2a15e9bd0>]



In [1]:

    
print('# Cyl\tPressure(PSI)')
for i in numpy.arange(0,len(quantity_cylinders),1):
    print ('  ' + str(quantity_cylinders[i]) + '\t' + str(pressure_final[i]))









    



# Cyl	Pressure(PSI)






    



---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-1-902235fcd9e8> in <module>
      1 print('# Cyl\tPressure(PSI)')
----> 2 for i in numpy.arange(0,len(quantity_cylinders),1):
      3     print ('  ' + str(quantity_cylinders[i]) + '\t' + str(pressure_final[i]))

NameError: name 'numpy' is not defined

Pressure Drop calculations

Collecting K-values of fittings, connections, etc...



In [ ]:

    
"""

"""

Works Cited

Cengel - Thermodynamics