High-Altitude Research Balloon Design: Questions Answered

[physicsCU]

For a lab I am working on, we are designing a high-altitude research balloon.

I have some questions though.

1. How do I calculate the volume of a zero-pressure balloon? By taking my mass of the body over the density of the air at altitude, does this give me the volume of gas needed at that altitude? But the zero-pressure has a larger envelope that isn't filled so that the gas expands.

2. From question 1, how would I figure out how much lifting gas i needed at the ground? Is there a formula I can use?

3. How do I compensate for the diurnal cycle to maintain a specific altitude?

Thanks for the help!

 

[lightgrav]

surely you mean "zero gauge pressure" ...
This is P_atm = 10^5 N/m^2 at ground!
Bouyant Force is (rho_displaced)(V_displaced)g
As P decreases, V of the gas increases
. . . but not for your payload!
Unless you heat it, lifting effectiveness
will decrease consistently as it rises.

I have only half-baked ideas for T stability!
Good Luck!

 

[quicknote]

I am happy to provide some guidance for your high-altitude research balloon design. Here are my responses to your questions:

1. To calculate the volume of a zero-pressure balloon, you will need to consider the weight of the payload, the density of the air at the desired altitude, and the expansion of the gas inside the balloon. The formula you mentioned, mass/density of air, will give you the volume of gas needed for the balloon to achieve neutral buoyancy. However, as you mentioned, the gas will expand as the balloon ascends, so you will need to account for this expansion in your calculations. You can use the ideal gas law (PV = nRT) to calculate the volume of gas needed at the ground and then adjust for expansion as the balloon rises.

2. To figure out how much lifting gas you need at the ground, you can use the ideal gas law as mentioned above. You will also need to consider the weight of the payload, the weight of the balloon envelope, and any other components such as cameras or sensors. It is important to carefully calculate the necessary lifting gas to ensure that the balloon can reach and maintain the desired altitude.

3. To compensate for the diurnal cycle, you will need to consider the changes in air temperature throughout the day. As the temperature changes, the density of the air will also change, which can affect the altitude of the balloon. One way to compensate for this is to use a control system that can adjust the volume of the lifting gas to maintain a constant altitude. This control system can be programmed to respond to changes in temperature and make necessary adjustments.

I hope this helps with your high-altitude research balloon design. It is important to carefully consider all factors and make precise calculations to ensure a successful and accurate research mission. Best of luck with your lab!