How Can You Model Coolant Cold-Side Temperature and Mass Flow Rate?

[Jay_]

Hi,

I had been communicating with Chestermiller for the past many months and I modeled the exhaust gas flowing through the pipe of a car.

Now, I had problems with the temperature sensor used, so this model couldn't be applied very well and its been a difficult time due to that. I have to complete this project by the end of this month, and I see no way out. I really need the help of you all.

At this point I have data for the following :
1. Vehicle Speed
2. Acceleration log (I created this one from the vehicle speed, by slope values between consecutive readings)
3. Engine Speed
4. Air flow into the engine (kg/s)
5. Coolant Temperature at the thermostat side

Is there a way I could model, either through available literature or equations in physics -
1. The Coolant cold-side temperature
2. The mass flow rate of the coolant

I need these two to calculate the ENERGY given off as heat through the coolant. So, I have a link that gives me the specific heat of the coolant at various temperatures. But I need some good estimate OR calculation for the coolant cold-side temperature and the mass flow rate as a function of any of the 5 'inputs' above.

This is rather urgent. I can understand if members won't give me answers directly, but quick guidance would really help. Thank you.

 

[Achy47]

I understand your frustration with the difficulties you have encountered during your project. I can offer some guidance on how you can model the coolant temperature and mass flow rate using the available data you have.

To estimate the coolant cold-side temperature, you can use the energy balance equation, which states that the heat absorbed by the coolant is equal to the heat given off by the engine. This can be represented as:

Q = m*Cp*(T2 - T1)

Where:
Q = heat absorbed by the coolant
m = mass flow rate of the coolant
Cp = specific heat of the coolant
T1 = initial temperature of the coolant
T2 = final temperature of the coolant

Using this equation, you can calculate the coolant cold-side temperature (T1) by rearranging the equation as:

T1 = T2 - (Q/(m*Cp))

To calculate the mass flow rate of the coolant, you can use the ideal gas law, which states that the mass flow rate is equal to the density of the coolant multiplied by the volumetric flow rate. This can be represented as:

m = ρ*V

Where:
m = mass flow rate of the coolant
ρ = density of the coolant
V = volumetric flow rate of the coolant

You can calculate the density of the coolant using the ideal gas law, which states that:

ρ = (P*M)/(R*T)

Where:
P = pressure of the coolant
M = molar mass of the coolant
R = universal gas constant
T = temperature of the coolant

You can estimate the pressure of the coolant using the air flow rate into the engine and the engine speed, as well as the temperature of the coolant at the thermostat side. You can also use the ideal gas law to estimate the temperature of the coolant using the pressure and density.

In summary, by using the energy balance equation and the ideal gas law, you can estimate the coolant cold-side temperature and mass flow rate. I recommend consulting literature on thermodynamics and heat transfer for more specific equations and calculations that can help you with your modeling.

I hope this helps and wish you the best of luck in completing your project by the end of the month.