Dimensional Unit Analysis Applications for Heat Pipe Design

This article explains the dimensional unit analysis applications used for heat pipe design.

Heat pipe: It is a two-phase, closed, heat transfer device with high heat transfer capability. While it can be made classically in a circular shape (pipe type), it can also be made in planar or many different shapes. The heat pipe essentially consists of a closed, air-emptied chamber containing some working fluid. A suitable wick is placed on the chamber wall to regulate the flow of the working fluid.

During operation, the heat in the evaporator area evaporates some of the working liquid and in a short time the interior of the chamber becomes saturated with pure vapor. Since the chamber wall in the condenser region will be relatively cold due to heat withdrawal from the system, condensation begins in this region.

The condensed liquid particles return to the evaporator and the cycle is completed. Gravitational force or capillary, centrifugal, osmotic, magnetic, etc. forces are used to bring the condensed fluid back to the evaporator. The most commonly used method is to take advantage of capillary forces.

The fluid, which transforms from gas phase to liquid phase by giving up its latent heat in the condenser, is returned to the evaporator with the help of a wick with a porous structure in the heat pipes. This porous structure can be knitted or woven materials from a separate material, or it can be a groove-shaped mechanically formed on the inner surface of the heat pipe, or a porous structure produced by powder metallurgy. Depending on the operating conditions, many different fluids can be used as heat carrier fluids through phase transformation in the heat pipe. The most commonly used fluids at medium temperatures are water, methanol, ammonia and other refrigerants. Aluminum, copper, steel, ceramics or other materials that can work in harmony with the working fluid used, depending on the operating conditions, can also be used as heat pipe materials.

Heat pipes can be manufactured in a wide temperature range, in different sizes, in fixed or flexible shapes, cylindrical, planar, rotational or in accordance with the place of use and purpose. It is possible to use heat pipes and systems in many other industrial applications, from cooling computer CPUs to nuclear power plants, from their use in spacecraft to the electronics industry, from controlling various processes to solar energy applications, air conditioning facilities and many other industrial applications. In addition, it can be used in both air conditioning systems and in the design and application of systems that provide heat recovery from high-temperature waste exhaust gases.