Search results

This paper aims to introduce a new type of analysis method to seek the actual working performance of the regulatable dry gas seal, including equilibrium film thickness, stiffness-leakage ratio and so on. Additionally, a parametric optimization of the hydrostatic structure is completed for this kind of seal.

From the point of axial force balance based on gas lubrication theory, a new analysis method, the Gas Film Divided Method, has been introduced. A four-factor and three-level hydrostatic structural parameters test scheme is designed by means of Central Composite Design test and then the hydrostatic structural parameters of regulatable dry gas seal were optimized. Three types of regulatable dry gas seal have been designed and manufactured to verify the theoretical analysis by measuring the equilibrium film thickness and inward leakage.

The results indicate that the numerical values of the Gas Film Divided (GFD) method agree well with the experimental ones. Test proves that the Central Composite Design test could achieve optimized hydrostatic structural parameters of regulatable dry gas seal effectively.

For validating the correctness of the GFD method, an experiment study of the regulatable dry gas seal is being carried out where atmosphere is selected as the lubricant for the sake of safety. Soon after, the author will discuss the application in the new paper.

The introduction of the GFD method proffers important insights to seek the performances of regulatable dry gas seal under the actual working conditions. The detailed optimal values of the hydrostatic structural parameters were given by the theoretical research which may be helpful for the design of regulatable dry gas seal.

Due to the market trend of low-volume and high-variety, the manufacturing industry is paying close attention to improve the ability to hedge against variability. Therefore, in this paper the assembly line with limited resources is balanced in a robust way that has good performance under all possible scenarios. The proposed model allows decision makers to minimize a posteriori regret of the selected choice and hedge against the high cost caused by variability.

A generalized resource-constrained assembly line balancing problem (GRCALBP) with an interval data of task times is modeled and the objective is to find an assignment of tasks and resources to the workstations such that the maximum regret among all the possible scenarios is minimized. To properly solve the problem, the regret evaluation, an exact solution method and an enhanced meta-heuristic algorithm, Whale Optimization Algorithm, are proposed and analyzed. A problem-specific coding scheme and search mechanisms are incorporated.

Theory analysis and computational experiments are conducted to evaluated the proposed methods and their superiority. Satisfactory results show that the constraint generation technique-based exact method can efficiently solve instances of moderate size to optimality, and the performance of WOA is enhanced due to the modified searching strategy.

For the first time a minmax regret model is considered in a resource-constrained assembly line balancing problem. The traditional Whale Optimization Algorithm is modified to overcome the inferior capability and applied in discrete and constrained assembly line balancing problems.