How would you measure the temperature that water boils at when the pressure is 11.5 psia?

Question

I am wondering what formula to use

Answer 1

For your question of 11.5 psia the boiling point is 199.9 F. But you asked about formulae for this so here that is, too.

There are formulae for this. The one you need is for the saturation line of water. These forulae are determined empirically and the result is a polynomial fit. Everything is done relative to the critical point of water which is:

Pc = 3208.234 psi
Tc = 1165.14 R

(R is degrees rankine which is just degrees F plus 459.7

For any temperature in Rankine (T), define a dimensionless temperature t = T/Tc

Next figure A:

A = -7.6912 t - 26.0802 t^2 - 168.1707 t^3 + 64.2329 t^4 - 118.9496 t^5

Now figure B as:

B = 1 + 4.1671 (1 - t) + 20.9751 (1-t)^2

Figure C as:

C = (1 - t)/(10^9 * (1 - t)^2 + 6)

The pressure corresponding to your boiling temperature T is then:

P = Pc*e^(A/(B*t) - C)

Answer 2

Are you asking how to (physically) measure the temperature?
In that case, it is both easy to do and dangerous to do.
Please note that 11.5 psia (absolute) is actually 26.2 psig.
That means that you are measuring at very high pressures.

First, you have to make sure that the container where you place the water is strong enough to sustain and not break at well over 26.2 psig. This is dangerous, so you make sure of all safety precautions before embarking on such an experiment.
In any case, knowing that water boils at 100 C at atmospheric pressure, then you expect the temperature to be much, much higher.

Or. easily, you can get the temperature from a lot of published TABLES or data of the boiling point of water at different temperatures. Specifically, you can "google" boiler operations.

Answer 3

There is not a formula for calculate such temperature changes.BUT ıT İS ON EXPERİMENTALLY WE KNOW THAT the temperature water boils at when the pressure on it is 11.5 psia.It is 513 deegrees centigrade.