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Davoud Mirzaei, Saeed Amini,
Volume 22, Issue 2 (1-2022)
Abstract
Today, the application of ultrasonic tools in various processes such as machining, welding, homogenizing, etc., has become widespread. One of the most important and key components in the transfer of acoustic energy in emulsion homogenization applications is the ultrasonic horn. This part is stable from the point of view of energy, but the amount of vibration amplitude can be changed by changing the shape and material. The purpose of this paper is to analyze the multistage ultrasonic horn to achieve the desired vibration amplitude in various applications. Optimal horn design has been done with the aim of increasing the amplitude of vibration, increasing and distributing the wave transmission surface and considering the strength of the horn, the appropriate length to diameter ratio to achieve uniform cavitation in the emulsion. The goal is to achieve a horn with a high amplification factor and a larger and wider radiation area at the end and lateral area of the horn. The high vibration amplitude and wave propagation area at the tip and the lateral area of the horn increase the amount of cavitation in the emulsion process, and the wider the wave propagation regions, the more efficient the homogenization process will be.
Amin Salimi, Alireza Riasi,
Volume 23, Issue 4 (3-2023)
Abstract
Regenerative pumps are pumps with a very low specific speed. The main characteristic of regenerative pumps is the ability to produce high heads at low flow rates. In this article, numerical and experimental methods have been used to analyze and improve the performance of regenerative pumps and also to investigate the effect of leakage flow around the impeller. In order to validate, an experimental test circuit of regenerative pumps has been designed and built. The comparison of the numerical and experimental results have a good agreement, which indicates the high accuracy of the numerical simulation. Based on the results of the study, we conclude that increasing the geometric thickness of the leak leads to an increase in mixing the high-pressure fluid of the outlet nozzle with the low-pressure fluid of the inlet area, leading to a decrease in the generating head generated by the regenerative pump. The performance parameter of efficiency will also decrease significantly by increasing the geometric thickness of the leakage to 0.4 mm compared to the original geometry with a leakage of 0.26 mm. On the other hand, reducing the leakage thickness to 0.2 mm will lead to the improvement of the functional parameters of the head and the efficiency of the reproducing pump. Also, the ideal geometry without leakage has been introduced and calculated for the maximum and theoretical limit of head and efficiency parameters.
