Cooling

More than 50% of energy used in combustion goes into heat[citation needed]. Heat is also generated by the turbulence of the air in the intake and cylinder, as well as friction from the engine's internals. A system is needed to keep the engine within it's operational temperature range.

Theory

Cooling systems are designed to dissipate the unwanted thermal energy. Systems are often designed around heat exchangers (HEXs), allowing for efficient exchange of heat from a hot fluid to a cooler one. There are three main methods of heat transfer;

• Conduction: Heat transfer over a temperature differential without motion between the materials
• Convection: Heat transfer over a temperature differential with fluid motion between the materials
• Radiation: Heat transfer due to by energy emitted from the unstable nature of a hot material (shitty definition, but the best I have)
  • Heat transfer in the form of electromagnetic radiation emitted by bodies above absolute 0 (wikipedia says its a function of distributing entropy, not sure we're gonna get a simple, and easy answer here)

A heat exchanger (HEX) is normally designed to optimize the heat transfer between two fluids using conduction and convection. The most common HEX is an water to air cooler, meaning it transfers heat between the hot water and the cooler air. These HEXs have a few distinct characteristics, full metal construction, thin metal fins in the streamwise direction, water inlets on top and bottom, with air inlets on the front and back. The metal construction is due to a low conductive heat transfer coefficient within the metal in addition to a low specific heat. These factors allow the metal rapidly conduct heat from the hotter internal water channels to the cooler metal fin tips. The fin structure is to maximize convection heat transfer by increasing the surface area the air flows over. The convection heat transfer coefficient is also a function of the airspeed passing the fin, allowing for 'forced convection' where a fan and or vehicle speed is used to impart an inlet speed to the system.Behavior(function?) of radiators vary heavily based upon water channel sizes, fin spacing, and a plethora of other characteristics.

Cooling Power

The amount of thermal power that the engine puts into the water has to be the same as the thermal power the radiator dissipates at steady state.

Needed Cooling Power

The rule of thumb is that 1/3 of the power you put into the engine in the form of fuel flow turns into heat. 1/3 becomes the power that turns the wheels and the last third comes out the exhaust or gets dissipated over the air [citation needed]. This ratio means that the power the radiator has to dissipate is approximately the same as the power sent to the wheels.

You have to keep in mind though that you don't drive full throttle all the time, so you have to average the engine power over the hole stint. You can do that for example by measuring the fuel consumption of your engine. I don't know how accurate that it though, because I've never done it. Also don't mind power peaks, like on a long straight, because the thermal capacity of your coolant is so big that it compensates that easily.[citation needed, just bc yours was big enough, doesnt mean everyone's is]

Finding average power output of the engine is one way to determine necessary cooling power for the engine. This can be accomplished by measuring fuel consumption or engine torque/vehicle velocity (P = FxV).

Getting that cooling Power

There are a couple of things that influence how much power the cooling system has:

• Radiator size: This is that you want to get right. It has by far the biggest impact.
• Water flow rate: Basically neglegtible. If you switch from a average sized pump to one with twice the flow rate you just get 1 or 2 Watt of additional power. Let's say the air has 30°C and your water 100°C when it enters the radiator and 95°C at the exit of it. Now you swap pumps and the bigger one makes the water leave the radiator at 97°C. You now have increased the temperature difference between the air and water from 67.5K to 68.5K or by 1.5%. This means your cooling power also increased by 1.5%. [citation needed]
  
  • Not basically negligible, just dimishing returns, if you have 0 water flow rate, you'll get close to 0 cooling no matter what else you do, if you have a properly sized water pump and swap to a bigger one, you'll see limited gains. If the water flow is too low, you won't be able to send enough heat from the engine to the radiator.
    
• Airflow: A front wing could make the air go over your radiator and make the engine go boom.
  • Also shrouds are said to do stuff.
  • Fan - forced convection
• The angle of the radiator: You can angle it to about 30° (some even say 45°) relative to the airflow without any significant loss in cooling power. [citation needed]
  
• single pass v double pass

Radiator Types

cross flow / downflow radiator, radiator form factors, and why we all use them

System Design

Hosing

type and sizing

Routing

keep it short and straight

Data and Data collection

see Data Acquisition

Other applications

Brake cooling

• Convective
  • ducting
  • theyre spinning hot disks, they have natural convection
• Radiation

Oil cooling

why you would want to cool oil

• If it boils or denatures bad things happen - Novotny
• thanks, lol, just a placeholder, isnt meant to be a question, poor phrasing on my end - simon
• all good, I was confused :')

Driver cooling

lmao