LED lighting fixture radiator profile aluminum extrusion

Aluminum profile has the advantages of light weight, beautiful and durable, high heat dissipation rate, good shapeability, etc., and has been widely used in air conditioners, coolers and radiators. In my country, the use of aluminum profiles for radiators is becoming more and more popular, and aluminum extrusion is the main form. This is because the extrusion-formed blanks have a good size consistency, a short production cycle and a relatively low cost.

    LED heat dissipation methods include radiation, conduction and convection.

    Radiation means that the body emits infrared rays to dissipate heat. When the skin temperature is higher than the ambient temperature, the body's heat is radiated away. The amount of radiation heat is related to factors such as skin temperature, ambient temperature and effective radiation area of the body. In general, radiant heat dissipation accounts for 40% of the total heat dissipation. Of course, if the ambient temperature is higher than the skin temperature, the body will absorb radiant heat. Steel workers work in front of the furnace, and farmers will also encounter this situation when working in the fields under the sun in the hot summer.

    Conduction is the way the body emits heat by transferring molecular kinetic energy. When the human body is in direct contact with objects that are cooler than the skin (such as clothes, beds, chairs, etc.), heat is transferred from the body to these objects. Clinically, using ice caps and ice packs to cool patients with high fever uses this principle.

    Convection is the flow of air, which uses air as a medium for heat dissipation.

    When the heat is transferred to the top of the radiator, it needs to be dissipated to the surrounding environment as soon as possible. For the air-cooled radiator, it is necessary to exchange heat with the surrounding air. At this time, heat is transferred between two different media. The formula to follow is Q=αXAXΔT, where ΔT is the temperature difference between the two media, that is, the temperature difference between the radiator and the surrounding air; and α is the thermal conductivity of the fluid After the heat sink material and air composition are determined, it is a fixed value; the most important A is the contact area between the heat sink and the air. Under the premise that other conditions remain unchanged, the volume of the heat sink is generally limited. , The space in the case is limited, which will increase the difficulty of installation if it is too large. By changing the shape of the radiator, increasing its contact area with the air and increasing the heat exchange area are effective means to improve heat dissipation efficiency. To achieve this, the surface area is generally increased by using fin-type design supplemented by surface roughening or threads.

    After the heat is transferred to the air, the temperature of the air in contact with the heat sink will rise rapidly. At this time, the hot air should be as far as possible to take away the heat with the surrounding cold air through heat exchange methods such as convection. , The main method is to increase the speed of air flow and use a fan to achieve forced convection. This is mainly related to the design of the fan and the wind speed. The efficiency of the radiator fan (such as flow rate, wind pressure) mainly depends on the fan blade diameter, axial length, fan speed and fan blade shape. The flow rate of the fan mostly adopts CFM as the unit (English system, cubic feet/minute), a CFM is about 0.028mm3/minute flow.

    Aluminum radiator is the most common radiator in the early days. Its manufacturing process is simple and low in cost. So far, aluminum radiator still occupies a considerable part of the market. In order to increase the heat dissipation area of its fins, the most commonly used processing method for aluminum radiators is aluminum extrusion technology. The main indicators for LED light controllers to evaluate an aluminum radiator are the thickness of the radiator base and the Pin-Fin ratio. Pin refers to the height of the fin of the heat sink, and Fin refers to the distance between two adjacent fins. The Pin-Fin ratio is the height of the Pin (excluding the thickness of the base) divided by the Fin. The larger the Pin-Fin ratio means the larger the effective heat dissipation area of the radiator and the more advanced the aluminum extrusion technology.