Cavitation erosion of silver plated coating considering thermodynamic effect

SUMMARY Cavitation often occurs in inducer pumps of space rockets. Silver plated coatings on the inducer liner face the damage of cavitation. In this study, we carried out cavitation erosion tests using silver plated coatings with different thermodynamic parameters at a constant cavitation number. Then we carried out cavitation erosion tests using some liquids with the same thermodynamic parameter and cavitation number as liquid oxygen. The thermodynamic parameter proposed by Brennen was used. The liquids used for the cavitation erosion tests were water, ethanol and hexane. We discuss the relation between the thermodynamic parameter and the mass loss rate, and the relation between acoustic impedance and the mass loss rate

Influence of Thermodynamic Effect on Blade Load in a Cavitating Inducer

Distribution of the blade load is one of the design parameters for a cavitating inducer. For experimental investigation of the thermodynamic effect on the blade load, we conducted experiments in both cold water and liquid nitrogen. The thermodynamic effect on cavitation notably appears in this cryogenic fluid although it can be disregarded in cold water. In these experiments, the pressure rise along the blade tip was measured. In water, the pressure increased almost linearly from the leading edge to the trailing edge at higher cavitation number. After that, with a decrease of cavitation number, pressure rise occurred only near the trailing edge. On the other hand, in liquid nitrogen, the pressure distribution was similar to that in water at a higher cavitation number, even if the cavitation number as a cavitation parameter decreased. Because the cavitation growth is suppressed by the thermodynamic effect, the distribution of the blade load does not change even at lower cavitation number. By contrast, the pressure distribution in liquid nitrogen has the same tendency as that in water if the cavity length at the blade tip is taken as a cavitation indication. From these results, it was found that the shift of the blade load to the trailing edge depended on the increase of cavity length, and that the distribution of blade load was indicated only by the cavity length independent of the thermodynamic effect

A Novel Method for Observation of the Mandibular Foramen: Application to a Better Understanding of Dental Anatomy.

Cone-beam computed tomography gives us much useful morphological information about the mandibular bone. Many studies of the mandible include findings from this technique. However, there have been no endoscopic studies of the mandible. Sixteen sides of eight dry mandibles resected from cadavers (age range 38-83 years) were examined by endoscopy. The head of the endoscope was 2.0 mm in diameter. We examined the mandibular foramen, lingula, mylohyoid groove, and mandibular canal. The mylohyoid grooves showed variations such as double grooves and canals. The mandibular lingula was located superior or medial to the the mandibular foramen. In a single case, the medial wall inside the mandibular canal showed a porous surface. The retromolar canal was observed in three sides. None of the images in the present study have been seen in other studies. Observation of the retromolar canal from the mandibular canal in particular can help dental students as well as oral and maxillofacial surgeons to understand its morphology. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1875-1880, 2017. © 2017 Wiley Periodicals, Inc