Design a Porsche Radiator for Water Cooled 250HP Engine

In summary, the conversation discusses designing a custom radiator for a water cooled engine in a Porsche. The main challenge is determining the necessary area and air flow, taking into account the 250 HP power rating and 35% efficiency. The conversation also mentions the importance of considering worst case scenarios and the potential difficulties of calculating air flow. Recommendations are made to consult a thermo engineer and utilize available resources for radiator sizing. Finally, the purpose of the engine swap is questioned.
  • #1
brouser
3
0
I am putting a water cooled engine in a Porsche and want to design a custom radiator. How do I calculate the area necessary, air flow across this area, and temperature under different conditions assuming the power rating of the motor is 250 HP and is probably 35% efficient at best ? I have a mechanical engineer who works for me but the size he came up with does not seem to match what I see in production vehicles.
 
Engineering news on Phys.org
  • #2
The basic heat exchanger equation is
[tex]Q = UA \Delta T_{lm}[/tex] where
Q = heat transfer rate
U = overall heat transfer coefficient
A = Area of heat transfer
[tex]\Delta T_{lm}[/tex] = log mean temperature difference between the two media exchanging heat.

The difficult part is coming up with U. It is usually found by coupling this equation with the energy balance for the system and iterating a result. It's not a straight forward process.

Chances are the reason why the estimated area your ME came up with is because a radiator has an incridible amount of perforations and bends in it to increase the overall heat transfer area while not increasing the overall envelope of the radiator.
 
  • #3
More things to consider:

Your engine might be 35% efficient "at best". However, have you considered "at worst"?! I'm not being facetious, but you won't have much problem when the engine is really working (140mph down the autobahn). You're going to come unstuck when you hit the traffic, you have no ram-air effect, and the poor thing is trying to dump an insane amount of heat out through an inadequately sized rad.

Have you had an opportunity to do a heat balance on the engine, or are you still at the drawing board stage? When we specify a new radiator, it's pretty much a full-time job for the thermo engineer to do the calculations and predictive work.

I wouldn't set about trying to calculate the air flow across the radiator. This is going to be something decided for you, essentially by the package constraints and the heat rejection at varying speeds, based on the possibility of (say) a 45 deg C ambient.
 
  • #4
Try the Lytron website for radiator sizing.
 
  • #5
Lol I guess this is the day everyone doing a watercooled swap into an aircooled car is coming to the forum for help! Check out my post "airflow thru radiator". If you go to kennedy engineering's website they have a lot of useful information in their catalog that is avaliable for download regarding radiator sizing and also have weight info of engines and such.
 
  • #6
If you can, I would just use the radiator that was designed for whatever engine you are running, that way you know that it is up to the task without going larger than you need, and if anything should happen to your radiator, like a rock damaging it or something, you know you can get a replacement at your local autoparts store, all without spending big bucks on a custom radiator
 
  • #7
Why are you doing this?
 
  • #8
Note that the OP was made 2 and a half years ago, and he's only made 3 posts...
 

1. How do you determine the size and shape of the Porsche radiator for a water cooled 250HP engine?

The size and shape of the Porsche radiator are determined by several factors, including the engine's power output, cooling system capacity, and aerodynamics. Additionally, the radiator's design must take into account the vehicle's overall weight and space constraints. Computer-aided design (CAD) tools are often used to optimize the radiator's size and shape for maximum efficiency.

2. What materials are commonly used to manufacture Porsche radiators for high-performance engines?

The most common materials used in the manufacturing of Porsche radiators for high-performance engines are aluminum, copper, and brass. These materials are lightweight, have excellent heat transfer properties, and are resistant to corrosion and high temperatures. In some cases, manufacturers may also use composite materials such as carbon fiber to further reduce weight and improve performance.

3. How do you ensure the Porsche radiator can handle the heat generated by a 250HP engine?

To ensure the Porsche radiator can handle the heat generated by a 250HP engine, engineers use a combination of computer simulations and physical testing. The radiator must be designed to withstand the high temperatures and pressures generated by the engine, as well as the heat generated by the surrounding components. Thorough testing is conducted to verify the radiator's performance and durability under various operating conditions.

4. What features should a Porsche radiator have to optimize cooling for a 250HP engine?

A Porsche radiator for a 250HP engine should have features such as a high number of cooling fins, a large surface area, and efficient airflow design. These features help to maximize the radiator's heat dissipation capabilities, allowing it to effectively cool the engine. Additionally, the radiator should be positioned in a way that allows for proper air flow and should have a high-quality cooling fan to aid in heat dispersal.

5. How do you determine the ideal placement of the Porsche radiator in the engine bay?

The placement of the Porsche radiator in the engine bay is determined by a combination of factors such as space constraints, aerodynamics, and the location of other engine components. The radiator should be positioned in a way that allows for efficient airflow and does not obstruct other vital engine components. Computer simulations and physical testing are often used to determine the optimal placement of the radiator for maximum cooling efficiency.

Similar threads

Water cooler radiator with unusual air flow direction
    • Mechanical Engineering
Replies
3
Views
573
How to design hydraulic system and size cooler
    • Mechanical Engineering
Replies
6
Views
1K
Cleaning of the finned tubes on gas cooler without disassembling
    • Mechanical Engineering
Replies
7
Views
982
Undefined log-mean temperature in heat exchanger design
    • Mechanical Engineering
Replies
3
Views
1K
Are Two Fans Better Than One?
    • Mechanical Engineering
Replies
6
Views
414
What is the Cooling Time for Steel Tubes with Ambient Nitrogen Gas Flow?
    • Mechanical Engineering
Replies
7
Views
2K
Automotive Ozone Enhanced Combustion of Water/Diesel Emulsion in CI Engines
    • Mechanical Engineering
Replies
6
Views
1K
Underground pump vault airflow considerations
    • Mechanical Engineering
Replies
15
Views
788
Venturi Effect based thought experiment
    • Mechanical Engineering
2
Replies
58
Views
3K
Could we make a practical solar fridge?
    • Mechanical Engineering
Replies
30
Views
2K

Hot Threads

Recent Insights

Back
Top