Assignment: Hydraulics
Robert Boyle and Guy Lussac described the relation between temperatures and pressures of gasses. The first balloon was launched in August 1783 by Jacques Charles and the Robert brothers. The weird vehicle was attacked by terrified villagers.
Gas balloons are still in use today for weather and atmospheric monitoring.
Figure 1. A rubber balloon for atmospheric testing is launched. Engineer the balloon in such a way that it reaches a height of 15 km.
A balloon for atmospheric testing is to be launched. Your engineering task is to make sure that the balloon reaches the correct height. Assume that the coefficient C that describes the tension of the rubber balloon (C) equals C = 30000 pa.m3(equation in figure 1b). The temperature change with altitude can be assumed linear with a coefficient of -6°C.
The tension in the balloon is determined by the elasticity of the rubber sheet and the thickness of the membrane which decreases as the radius of the balloon increases. Also the elasticity of rubber varies with its elongation.
1. Derive an equation for the mass density of air as a function of the height using the pressure and temperature equations. What is the air density, temperature and pressure at an altitude of 15 km?
2. What should be the radius of the balloon at an altitude of 15 km when the balloon with measurement equipment has a mass of 10 kg and is in equilibrium?
3. [MATLAB] In previous case, what is the size of the balloon at ground level?