Effect of Geometric Parameters on the performance of Dry Gas Seal with Trapezoidal Grooves

Friction is created in the gas seals due to the relative motion of the two fixed and rotary surfaces, causing power dissipation, erosion, heat generation and temperature rise of the surfaces so a distance between two surfaces should be created. In the structure of Dry Gas Seals (DGS), the grooves on the rotating surface are created, which is the key to the gas penetration between the surfaces. The geometrical parameters of grooves would have substantial effect on the amount of leakage, so it is of high importance to indicate the best shape and operating condition of grooves. In this research, the effect of geometric parameters of a DGS with trapezoidal grooves on the leakage rate and open force is investigated. The geometric parameters are the depth of the triangular and square sections, the length of the groove, the angle of the square part and the angle of the groove. The length of the groove has a substantial impact on leakage, and by doubling the length, the leakage rate is raised to 58%. It is concluded that when the angle of the square section is 7° and the angle of groove is 22°, the minimum leakage occurs in the range of parameters studied. Taguchi algorithm is also applied to optimize the shape parameters of the groove to minimize open force and leakage of the seal. Optimal dimensions for grooves in the range of operating conditions in this study are triangle depth=3μm,quad-depth=10μm,Length=8mm,groove angle=18°,rectangle angle=5°. The same optimum conditions are obtained by considering energy and exergy terms.