Detailed study on stiffness and load characteristics of film-riding groove types using design of experiments

In the application of film-riding sealing technology, there are various groove features that can be used to induce hydrodynamic lift. However, there is little guidance in selecting the relative parameter settings in order to maximize hydrodynamic load and fluid stiffness. In this study, two groove types are investigated—Rayleigh step and inclined groove. The study uses a design of experiments approach and a Reynolds equation solver to explore the design space. Key parameters have been identified that can be used to optimize a seal design. The results indicate that the relationship between parameters is not a simple linear relationship. It was also found that higher pressure drops hinder the hydrodynamic load and stiffness of the seal suggesting an advantage for using hydrostatic load support in such conditions

Predicting Lift-Off Time When Deep-Frying Potato Dough Snacks

When frying potato snacks, it is typically observed that the dough, which is submerged in hot oil, after some critical time increases its buoyancy and floats to the surface. The lift-off time is a useful metric in ensuring that the snacks are properly cooked. Here we propose a multiphase mathematical model for the frying of potato snacks, where water inside the dough is evaporated from both the top and bottom surfaces of the snack at two receding evaporation fronts. The vapor created at the top of the snack bubbles away to the surface, whereas the vapor released from the bottom surface forms a buoyant blanket layer. By asymptotic analysis, we show that the model simplifies to solving a one-dimensional Stefan problem in the snack coupled to a thin-film equation in the vapor blanket through a nonlinear boundary condition. Using our mathematical model, we predict the change in the snack density as a function of time and investigate how lift-off time depends on the different parameters of the problem