A large fraction of the thermal energy generated in the engine of a car is rejected to the air by the radiator through the circulating water. Should the radiator be analyzed as an open system?

Yes

Explanation:

Type of control system

1. Open system

When mass and energy is allowed to pass through the system, then this type of system is called open system.

2. Close system

When only energy is allowed to pass through the system, then this type of system is called close system.

3. Isolated system

When mass and energy did not allowed to pass through the system, then this type of system is called isolated system.

In the engine radiator, mass of hot fluid enters and interact with the cold air then after heat transfer take place between these two fluids, that is why we can say that radiator is an open system.

It become necessity to use the radiator in all type of engine because it produce cooling effect to the engine cylinder. If temperature of engine cylinder will become too high then it will leads to the high thermal stresses and may be it will break the engine cylinder.