1. I want to know how much percentage of air is usually use for cooling the radiator? 2. what is the angle of air flow in the entrance of the air intake ( I know that it is related to the configuration of the front of vehicle but I want to know that is there any accepable domain for it or not? )

(1). At idle, when the car is not moving, it depends on the fan size, the rpm (say 600rpm) and the radiator design. I think, each car will be different. You can get it from the car manufactures. (2). When a car is moving, it will depend on the car speed. So, it is a variable. (3). When the engine is cold, there is no flow through the radiator. So, there is no cooling. In cold weather, the engine will remain cold longer and there will be no cooling at all. (4). Assuming one third of the energy is dissipated through the heat transfer, it is a function of engine size, rpm and loading I guess. (5). If you look for the fan spec on the after market parts, sometimes it will say the rpm and cfm (flow rate). Naturally, the installed performance will be different.