| Since 1980, the divided-flow adjustable-cross has been widely used in air-conditioning and ventilating duct systems in China. However, this brings about a problem that there have not been available data to determine its local resistance. Therefore, in order to meet the need of engineering, and based on the previous experimental study, the author analyses the significant factors of the adjustable-cross comprehensively, and obtains the coefficients of the local resistance of this duct fitting In this aspect, this study has its practicability. In view of the computer common use in HVAC, the author makes use of multiple linear regression model to fit the experimental data, and then obtains the regressive formulas for determining the local resistance coefficients of the adjustable-cross, which could be adopted by some HVAC programs. Also, at the end of this thesis, an applying example of the achievements is given. |
