Hole-Pattern Seals Performance Evaluation Using Computational Fluid Dynamics and Design of Experiment Techniques

Abstract

A main goal o f noncontacting mechanical seals is to provide minimal leakage during oper ation. This may be achieved by specifying a small clearance between the mating faces that is just enough to avoid rubbing contact while allowing some tolerable leakage. The amount of leakage flow is reduced through the acceleration and deceleration o f the fluid through a tortuous path, so the sealing performance depends on the geometric characteristics o f the leakage path. This study focuses on annular hole-pattern seals, which are noncontacting mechanical seals commonly used in high pressure compressors. A design o f experiments (DOE) approach is used to investigate the effects o f various geometric variables on the leakage rate o f a hole-pattern seal during normal operating conditions. The design space, defined by the ranges o f hole diameter, hole depth, axial space between holes and number o f holes in circumferential direction, is discretized using the simple random sampling method. Then, steady-state computational fluid dynamics (CFD) simulations are performed at each design point to evaluate seal performance. To better understand the sensitivity o f the hole-pattern seal leakage rate with respect to design variables selected, response surfa ces are built through its values at design points using quadratic polynomial fitting. The results show that the optimal solution had a better leakage control ability over the base model design. It is believed that the results o f this study will assist in improving the design o f annular hole-pattern seals.

Design of Experiments to Investigate Geometric Effects on Fluid Leakage Rate in a Balance Drum Seal

“…A classic example of DOE is a factorial design, invented by Fisher in response to the common misconception that to obtain in formation about the effect of a factor you must hold other factors in a given system at constant levels [11][12][13]. Instead, a 2k factorial design not only allows variation of multiple factors at a time but also allows for calculation of interaction effects between factors.…”

Detailed Study on Stiffness and Load Characteristics of Film-Riding Groove Types Using Design of Experiments

“…This is achieved using a design of experiments approach. Such techniques are becoming increasingly popular in recent years and have already been applied to several sealing problems including brush seals [17] and balance drum seals [18,19].…”

Gas-Expanded Lubricants for Increased Energy Efficiency and Control in Rotating Machinery

“…This chapter details the design of the Gas-Expanded Lubricants Seal Test Rig that will be used to study a variety of seals used for low-pressure liquids, GELs, multi-phase mixtures, and pure gases. A variety of bulk flow, computational fluid dynamics, and hybrid methods have been developed to model the performance of these seals [164][165][166][167][168][169]. The GEL Seal Test Rig will also serve to experimentally validate these methods as they are further developed and improved in the future.…”

“…The single-tooth The hole pattern seal cartridges have the same exact dimensions as the plain annular seals, but with the addition of the hole pattern on the seal face. Hole pattern seals have been found to reduce leakage and destabilizing cross-coupled stiffness forces in gas seals [124,135,140,164,166,169], therefore it will be interesting to see how they compare to plain annular seals in a liquid or GEL environment, particularly as the gas phase separates from the GEL as the pressure drops across the seal face. The hole geometry includes a 0.125" outer diameter, a 0.125" depth, and a 0.017" material gap between the edges of each hole pair.…”