Thesis 1 abstract
- 1. 3 LIQUID DROP EROSION / CORROSION Abstract The subject of this thesis is to study the liquid droplet erosion through two simulation approaches. A purely experimental by using the existing testing unit which lies in the materials lab in the basement of Mechanical Engineering Department, University of Western Macedonia and one using commercial software ANSYS CFX v.13 for fluid dynamics simulation of the operation of these tests. The first part measured the progressive mass loss of six metallic test pieces of three different materials (aluminum, brass and steel). The process was based on the ASTM G73 standard under which the specimens subjected to a simulation of the phenomenon case, where they are placed in a special device which has two water jets and a motor-wheel system. The specimens are placed in special holders on the wheel. Two water jets Impinge on them periodically. At regular intervals throughout the experiment was stopped so the the mass of the samples could be measured. When several measurements were collected the experiment stopped. The specimens of aluminum exhibited the greatest mass loss while the specimens with brass and steel showed significant oxidation. The slowdown of aluminum and brass pieces was evident. Then according to the model and after measurements were recorded and produced tables and charts, a comparison should be made with measurements that where done in the same unit, under the same conditions. The comparison was finally made with the results of former student’s V.Iordanou thesis, which distinguished a larger mass loss in the essays of this thesis. In the second part it was attempted to simulate the fluid mechanics of the testing operation. The mean to that was the commercial program ANSYS CFX. The simulation was divided into four individual pieces to produce better results. Initially, we studied the effect of air movement in the shell without the jets. Then we studied the two jets without the effect of the air on two occasions. One for if the jet does not conflict with the test piece and one in case of impact. For both of the cases, there was a study on the jet-air interaction. Finally, two runs were made for the case of the smaller speed water jet to study better the effect of air over them, and how they affect the impact force on the test piece. The air affects the finished package while there is
- 2. 4 significant difference between the power calculation model and the analytical calculation.