amir javanbakht

Liquid cooling systems play an essential role in various branches of industry. Most electrical and electronic circuits whose power supplies exceed a certain threshold, generating significant heat, employ water-cooling systems instead of air-cooling systems. This study numerically investigates a single-phase liquid cooling system using various nanofluids and innovative flow patterns. The objective of the study is the enhancing of cooling performance and the reducing of temperature in circuit boards. The finite volume method, implemented in the commercial CFD software, ANSYS Fluent, is employed to simulate the fluid flow and heat transfer within the system. Additionally, the pressure drop of the coolant flow is analyzed as a critical parameter. To optimize cooling performance, various flow patterns are explored to minimize the contact surface temperature of power supply components. These patterns include changes in the number of branches from three to five, variations in the width of the passage of the fluid flow beneath electronic components from 10 to 12 millimeters, location of the water channels closer by adding more fluid channels as well as by changing the width of the fluid manifold. Additionally, the impact of incorporating nanofluids is examined. Water-based nanofluids incorporating aluminum oxide and copper oxide nanoparticles at volume fractions of 1%, 3%, and 5% are employed to reduce the temperature of the contact surface of the power supply sources as much as possible. The results indicated that altering the flow pattern and the number of branches led to an optimized flow pattern that reduced the maximum temperature of the power supply components by up to 2.5 degrees Celsius compared with the baseline configuration. Furthermore, the addition of nanoparticles provided a modest temperature reduction of approximately 0.5 degrees Celsius.

Now a day centrifugal pumps are vital components of industries. Certainly, one of the most important specifications of centrifugal pumps are the performance curves. In the present work, performance curves of a centrifugal pumps are obtained by Computational fluid dynamics (CFD) and as an outcome, CFD results compare by practical curves. At the first step impeller and volute are designed with two standards and at the end former design completed by automatic design process using CFturbo software. For this purpose, full 3D-RANS equations in coupled with SST turbulence model are solved for several flow rate between 20% and 140% of the operation condition by means of a commercial code, CFX. This simulation is defined by means of the multi-reference frame technique in which the impeller is situated in the rotating reference frame, and the volute is in the fixed reference frame. Proposed simulation is based on a steady state flow, non-Newtonian, incompressible and constant property condition. Operation point is simulated to get the total head and then non-operation points are simulated to obtain performance curves. Practical curves and numerical ones are in good agreement, so numerical approach could be a perfect way to make centrifugal pump design better and easier. Indeed pump simulation with CFD approach can increase our knowledge about pump behavior such as consumption energy, trimming process and saving energy before we have any activities on the pump so the predictions have bettering and excise about any process on the pump.

Zona is caused by the reactivity of varicella zoster virus. The most prevalent effect of zona is Post Herpetic Neuralgia(PHN). PHN is a pain that can remain stably more than thirty days after skin losses. Despite the fact that there are different cures for PHN, none of them is certain. Some medications like capsaicin have herbal sources. Satureja khuzestanica is a plant which is indigenous to Lorestan and Khuzestan provinces and has proven effects on pain alleviation. This study investigated the effects of Satureja Khuzestanica essential oil on PHN. The study was carried out by clinical trails on fifty patients suffering from PHN. The patients were randomly divided into two groups. The experimental group received a solution containing the essential oil of Satureja khuzestanica with a five-percent density while the control group received the placebo. The pain intensities, before and after taking the medications, were recorded on a numerical scale. The results were analyzed using repeated- measures test, t-test, matched pairs t-test, and Mann-Whitney test. The average pain intensities in the experimental group befor and after taking the essential oil were 8.12±1.48 and 5.72±2.9 respectively. On the other hand, the average pain intensities in the control group before and after taking the placebo were 7.8±1.57 and 8.04±1.46 respectively. In addition, the men´s reaction to the medication was meaningfully more noticeable than the women´s. Sixty percent of the patients experienced the alleviating effects of the drug. The side effects of the drug were observed in nine patients in the form of erythema and burning that vanished in an hour. There were no statistically significant differences regarding sex and age variables of the two groups. The essential oil of Satureja khuzestanicais effective on alleviating PHN. It is more efficient than other medications regarding the effect starting time, the stability of effect, the acceptance, and the side effects.