Answer Key
Homework 2
2.611 Fall 2006
For part one I am giving credit for any reasonable answer.
For part two you can examine the equation itself to determine what you can change to increase
or as
Bonus :
Now simplify to:
Use only positive root
you could simplify further
but you can see the solution.
Any reasonable
estimate will work
for w,t.
You had to find total propulsive efficiency, pump pressure rise, mass flowrate, and total
hp delivered.
You could start anywhere, I chose to start with pressure rise:
Next I can rearrange the net thrust equation and solve for mass flowrate:
Now I can find ideal pump power, since I already gave you pump efficiency we can solve for power
delivered.
if
Now for the Flush:
if