The structure and shape of the heat pipe

Between the structure of the heat pipe is varied, the difference is very big. The minimalist paste structure form, as shown in figure 6-8-1, it has a closed shell, shell inner surface is covered with a layer of capillary structure of the porous material, called liquid-core absorption, it can be all kinds of wire mesh or around the junction of porous structure. Absorbing liquid core can be made of shell inside cover on the surface of the groove with a hole in the screen cover or some other can rely on MAO threading forces the liquid from the cooling period of delivery to the structure of the heating section. Many, many different kinds of liquid heat pipe core, commonly used is shown in figure 6-8-2 kinds of:

(a) screen liquid core, copper, bronze, brass, stainless steel wire mesh or various fiber fabric roll into layer and press on the inner wall of the shell.

(b) around the junction metal powder (or screen), the number 7 l core structure of suction fluid with low thermal resistance.

(c) sleeve to tank, pipe shell inner wall made axial straight flute, mio slot section can be rectangular, trapezoidal or triangular.

(d) road suction liquid core, if use screen into porous road, in order to increase the axial transmission ability. At this moment need to match using radial thread groove or other porous structure as the radial liquid transmission, the shape of the trunk road sucks fluid core can be varied.

(e) screen cover, a combination of absorption liquid core, liquid composite core can have different combinations, to improve the sleeve to the transmission capacity and the radial heat pipe thermal resistance is reduced.

Heat pipe is the use of phase change of the working medium for heat transfer, no transmission device and the power of the working medium of. So, to guarantee the normal work of the heat pipe, the first is that it must be kept completely sealed, any leakage can make heat pipe failure. The second is the tube can't have no non-condensable gas, if there is no non-condensable gas, can clog the steam to the condenser, eventually lead to tube failure, and even burn. There is a suction fluid core must be kept clean, otherwise it will reduce the capillary suction. In addition, the absorption liquid core must be clingy wall * if not, condensation of liquid and liquid core does not contact, you can't get back to the evaporator. Also, the tube shell material phase between each other must have the intermiscibility, otherwise it will produce no non-condensable gas or corrode, so that can make the heat pipe does not work. Commonly used a combination of working liquid and heat pipe solution as shown in table 6-8-2.

Heat pipe has a variety of geometric forms: straight, curved, cylindrical, short form, rigid, flexible, spiral, rings, and so on. The typical heat pipe shape as shown in figure 6-8 '3. Direction of the axis of the tube and steam flow direction - usually. If the size of the pipe and the axial length of the pipe used in the same order of magnitude or more than sleeve to the length, the structure is called a "steam rooms". Steam chamber can make the disk, parallel pipe or other forms.