Collision of water drops with a thin cylinder

The collision of water drops with a thin cylinder is studied. The droplet flight trajectory and the cylinder axis are mutually perpendicular. In the experiments, the drop diameter is 3 mm, and the diameter of horizontal stainless-steel cylinders is 0.4 and 0.8 mm. The drops are formed by a liquid slowly pumped through a vertical stainless-steel capillary with an outer diameter of 0.8 mm, from which droplets are periodically separated under the action of gravity. The droplet velocity before collision is defined by the distance between the capillary cut and the target (cylinder); in experiments, this distance is approximately 5, 10, and 20 mm. The drop velocities before the impact are estimated in the range of 0.2–0.5 m/s. The collision process is monitored by high-speed video recording methods with a frame rate of 240 and 960 Hz. The test liquids are water. Experiments and numerical simulation show that, depending on the drop impact height (droplets velocity) different scenarios of a drop collision with a thin cylinder are possible: a short-term recoil of a drop from an obstacle, a drop flowing around a cylindrical obstacle while maintaining the continuity of the drop, the breakup of a drop into two secondary drops, one of which can continue flight and the other one is captured by the cylinder, or both secondary droplets continue to fly, and the drop can be also captured by the cylinder, until the impact of the next drop(s) forces the accumulated drop to detach from the cylinder. Numerical modeling satisfactorily reproduces the phenomena observed in the experiment.

Finite Element Analysis of Installation Failures in Engine Cylinder-Liners

There exist concerns regarding the failures that occur during the installation of thin cylinder-liners of engines at the authorized and unauthorized service centers. Analyzing the probable causes from the points of view of the design, manufacturing, and authorized and unauthorized installation procedures define the problem. The problem involves the simulation of the process of press-fitting the liner into the cylinder bore. A choice of finite element analysis using commercially available software ANSYS helped the analysis of the probable causes of failure. Estimation of the probable loads experienced by the cylinder-liners during the procedures that exist in the installation-process paved the way to the definition of loads that prevail in the problem of relevance. Prediction of the nature of contacts that prevail in the current problem and the impact of the application of the loads enabled the definition of constraints for the simulation procedures. Reference material properties chosen in the conservative sense modeled the problem realistically. The evolution of the recommendations for the manufacturing and installation of thin cylinder-liners concluded the study.