Capillary Characteristics Of Small-scale Refrigeration Equipment

The capillary is the simplest throttle component applied in the small-scale refrigeration equipment and it can drop pressure of refrigerant. The diameter of capillary is usually from 0.5 to 2.5 mm and length of it is usually from 1 to 3 m. Though the structure of capillary is very simple, the flow of refrigerant in it is very complex. It has taken difficulty in design of refrigeration system. So matching capillary suitably in refrigeration system is the most important.At present, there is too much research on the flow characteristics; well the research on the design of length of the capillary is too little. The practical length of capillary can be obtained usually through experiment. In view of this, this thesis regards adiabatic capillary and refrigerant R22 as targets and does the following things:1. Study the academic and practical course of the flow of refrigerant in the adiabatic capillary. During the course, metastable phenomenon has been considered; well critical flux phenomenon is the most important. At the same time, this thesis also introduces another result of research on the critical flux phenomenon for understanding it deeply.2. Using the mathematical model of two-phase drift flow and considering the metastable phenomenon and critical flux phenomenon, a numerical simulation program is developed and applied in the design of length of capillary.3. Through this numerical simulation program, we can analyze the influence of all kinds of factors on the design of length and on the pressure of outlet of capillary. After that, we can get some useful trendlines among those factors for analyzing.4. Establishing an experimental table. Through it, some parameters of flow characteristic of refrigerant can be obtained for applying to the research. For example, we can analyze the variety of the characteristic parameters on the different length. At the same time, we also can prove the correct of the program through the experimental data.