Fast And Explicit Modeling And Analysis On Adiabatic Capillary Tubes

Capillary is an important closure member, which is widely used in refrigeration and heating devices. From perspective of the capillary application in the refrigeration system, when the diameter, flow, import and export parameters are known, the refrigeration system designers concern how to calculate the length of the capillary. Therefore, the aim to do the research of capillary tube flow calculation is to find out the relationship among diameter, length, flow, import and export parameters. To calculate the optimum flow can determine the optimum length, which can make sure the efficiency of the system is the highest. Currently, the calculation models of capillary flow at home and abroad are basically summed up in the following: 1) The flow calculation model based on energy conservation equation.2) Empirical correlation model. 3) Neural network models and so on. Although the model based on energy conservation has good versatility, but the calculation process requires constant iterative, which will make high demands on programming, and also affect the speed and stability of the algorithm. Since empirical correlation is related to numbers of parameters, it's easy to be wrong in the call of calculation, so the general is poor. The neural network model is too complex to implement. In order to find a fast calculation, simple formula form and high precision model, This article propose a new and fast calculation correlation for adiabatic capillary tube based on ASHRAE nomogram, and do analysis and comparison of data provided by literatures. The results show that ASHRAE nomogram model has very good accuracy.The main work in the paper is as follows:1)Establish energy conservation model based on homogeneous flow and propose iterative logic.2)Propose nomogram fast and explicit model, which is one of the highlights in this paper.3)Compare and analyze some experimental data, the results of conservation equation, empirical correlation and ASHRAE nomogram model. The results show that ASHRAE nomogram model has very good accuracy.To sum up this research work, this paper has two characteristics:1)Propose nomogram fast and explicit model for the first time.2)Detailed analyze the different factors which cause mass flow changes.