15 Applications of Fractal Theory in Sealing Performance Analysis on Premium Connection

The profile curves of seal surfaces are obtained after makeup and breakout test of premium connection, and then the surface profile of premium connection is characterized by means of W-M function model in fractal theory. The calculating software of Fractal method analysis is compiled by Visual C++ computer language basing on the established model. Fractal dimension D, scale coefficient C and characteristic scale coefficient G are calculated using structure function method. Based on steady laminar flow of gas in cosine-wave channel, the modified M-B contact model is established with fractal parameters, and the formula to calculate the gas leakage rate is given. The gas leakage rate is 5.08×10-5cm3/s by calculation. It shows that the sealing effect of premium connection with steel grade P110 is good.