Coron vs Aviation

[dov]

Hallo

 

I thought that I should give you a glimpse about something in common between Corona and Aviation. You may be surprised, but the fight against Corona has indeed a lot of common with aviation knowledge.

Thermodynamics of the human body and a turbo engine of an aircraft.

Well, do you know, that you really can produce supersonic gas? You do, if you are sneezing. The pressure ratio is higher than 2. If the ratio is 2 and above, you cause supersonic velocity of the gas you work with. The supersonic wave of the gas causes the sound which easily to hear. Even a fart, you can also notice the sound!

If we want to see the efficiency of a mask, quite easy! The gas seals of a turbo engine show us how easy it works. To seal a gas is much more easy, as to seal a fluid. The hot high pressure air after the compressor is the critical area. The principle is the throttle.

 

The throttle

A throttle is a cross-sectional constriction in a pipe and thus an inexpensive component for reducing the pressure of a fluid flow.

Every throttling process is irreversible. Since an idealized throttle is assumed to be adiabatic, this means that the specific entropy of the fluid behind the throttle is higher than in front of the throttle. It also follows from this and from the first law that the specific enthalpy of the fluid remains constant when passing through the throttle. (This applies as long as the speed and thus also the kinetic energy of the fluid does not increase significantly due to an increase in the specific volume and thus the volume flow.)

In any case, the pressure of the fluid drops as it passes the throttle. The temperature of the fluid, on the other hand, can rise as well as fall. The concrete behavior is described by the Joule-Thomson coefficient.

Note: With ideal gases, the temperature remains constant with ideal throttling, since the specific enthalpy remains constant and the enthalpy of an ideal gas in turn depends only on the temperature of the fluid:

 

dh=CpdT

 

What is important: You can minimize the gas flow by using a throttle, so that the mas stream goes close to zero. In our Corona case, even the virus transport can so be almost stopped. This is how your face mask works. To sheets of fabric have a wonderful result. The free enthalpy is reduced so far, since you come much closer to the pressure of your surrounding. The width of your gas stream is reduced to a minimum. Consider: If you reduce the gas stream drastically you also reduce the Virus load to your surrounding drastically.

 

 

The next thing I want to explain:

 

·        The number of infections ahead. Important is, to find all infected humans fast, they must report fast and you must test them fast. (in 24.00 hours).

·        And to track the provable companions. And to test them.

 

If the first step can not be done in 24 hours, you start to create an exponential increase. Why?

This remnant triggers the exponential function.

 

It is to compare when you are flying. Move the throttle slightly forward in horizontal stable flight. What happens is you accelerate, as long as increased drag does not cause a new equilibrium.

So, just a short explanation the Corona battle with thermodynamics and basic math.

 

 

Happy modelling

[Truro Model Builder]

I feel stupid now... 

[dov]

No worry at all.

1.   My message was, that the gas throttle can be used to seal high pressure gas against low pressure gas. The result is, that the mass stream of gas is reduced to an infinite amount. In this infinite mass stream you have also just an infinite amount of virus load.

2.   The math explanation shows you, that if health authorities work too slow in 24 hours, and leave some unchecked cases behind each day, the create an additional exponential function. This must be multiplied with the exponential function of infection by itself. This is the case in big towns all over Europe. Here in Vienna, they increased the workforce for infection determination and quarantine promulgation to additional 1000 persons yesterday. With in total 1500 heads you may control this big city.

3.   And one more idea: Keep in mind, normal infection needs two persons. One who has the virus and one who gets it. In a bar or crowd you may say you have 5 of more persons to receive it. So it triggers much faster, as in the ordinary equation calculated.

Happy modelling