116,327 views
2 votes
2 votes
Using the given temperature and pressures, determine: a) the diameter of the water scale model balloon (m), b) the weight of the scale model, c) the specific gravity of the buoyant material such that the model conditions will be similar to the full-scale balloon.

User Nicolai Harbo
by
2.4k points

1 Answer

21 votes
21 votes

Complete Question

Complete Question is attached below

Answer:

a)
D=0.7

b)
W=1787.5N

c)
\rho'=998.19kg/m^3

Step-by-step explanation:

From the question we are told that:

Hot air:

Temperature
T_a=360K

Pressure
P_a=100kPa

Distance
d=12m

Weight
W=1400N

Water:

Temperature
T_w=300K

Pressure
P_w=100kPa

Since we have The same Reynolds number

a)

Generally the equation for equal Reynolds number is mathematically given by

Re_{air}=Re_{water}

Therefore


(\rho V D)/(\mu_(air))=(p_(water)*V*D)/(\mu_(water]))


(100*12)/(300*0.28*1.81*10^(-3))}=(998*D)/(0.000890)


D=0.7

b)

Generally the equation for Weight of scale is mathematically given by


W=\rho*V*g


W=998*(4)/(3)*\pi*0.35^3*9.81


W=1787.5N

c)

Generally the equation for Density of buoyant material is mathematically given by


\rho'=(w)/(g*V)


\rho'=(1781.5)/((4)/(3)*\pi*0.35^3*9.81)


\rho'=998.19kg/m^3

Using the given temperature and pressures, determine: a) the diameter of the water-example-1
User Del Pedro
by
2.9k points