نشریه مهندسی مکانیک تبدیل انرژی
سال هشتم شماره 1 (پیاپی 26، بهار 1400)

The aim of this article is to analyze SEC critically in relation to refinery industrial energy efficiency. In this study, the effect of various parameters such as input energy carriers, output energy, API value, and input refining oil was investigated. Specific energy consumption of unit and standard criterion was obtained 2.30 and 3.06 Gj/ton, respectively, that the total specific energy consumption is 24.83% less than the standard criterion. The use of a high-tech process for promoting Green Productivity and increasing the degree of complexity is the most important parameter affecting the reduction of energy footprint, improvement of energy consumption criteria, and standardization of the Abadan oil refinery.

An appropriate technique for separation of particles in microfluidic system is the use of dielectrophoresis (DEP), a phenomenon referring to the motion of a particle in a non-uniform electric field due to the unbalanced electrostatic forces on the particle’s induced dipole. Therefore, in current study, separating platelet cells from red blood cells in a continuous flow using dielectrophoretics (DEP) mechanism is numerically investigated in microfluidic device. To this approach, COMSOL Multiphysics software is used. To verify the simulation, the results are compared to previous experimental data. The effects of different parameters including voltage, flow speed and frequency on the separation of platelets are studied in details. The results reveal that successful separation of platelets from blood cells are occurred by applying voltages. Low voltage causes platelet cells and red blood cells to exit from one side of the channel while high voltage causes the red blood cells to collide with the channel wall. According to condition, a range of voltage is suitable for current device to efficiently separate red blood cells and platelets. Also, with increasing particle inlet velocity, the separation takes place farther from the inlet, and the distance between the two consecutive isolated particles of red blood cells or platelets increases.

Due to the increasing use of hydraulic systems in different sectors of the industry, it is necessary to pay attention to the concept of energy consumption and to provide appropriate solutions to optimize energy consumption and recovery in hydraulic circuits. In this study, the effect of load on motor, effect of nano particles and capacity of accumulators were investigated on energy consumption, circulation oil temperature variations in the circuit and oil leakage in both circuit with base oil and nano-oil circuit. For this purpose, titanium dioxide nanoparticles (Tio2) as oil additives and accumulators with volumes of 1.5, 5 and 10 liters were used for energy recovery of the system. A hydraulic system was designed and assembled to conduct the research. The desired nano particles With concentration of 0.5 wt.% were mixed with a hydraulic oil and Was tested. The tests were performed in two modes, once with base oil and once with nano fluid (base oil in combination with titanium dioxide). The results showed that the application of nano particles as an additive to oil and energy recovery system with the help of accumulators had a significant effect on improving energy consumption, reducing circulation oil temperature and reducing oil leakage.

Data centres are enabled by the possibility that servers and its equipments are embedded in the network and it is a hardware that incorporates hardware such as servers , servers , switches , and routers , and other network equipment . Therefore , in a safe and secure space , it will provide you a coherent class to maintain the network equipment due to the constant heat release from the orcs , the management of air distribution systems and the cooling system in data centers to prevent the damage caused by excessive heat . the aim of air distribution systems is to solve the problems in the cooling of the data centers , including minimizing the return of hot air , the cold air and the removal of hot spots . also high cost of cooling systems can be reduced and their efficiency can be improved . index parameters , which include orc cooling index ( rci ) , input and return heat index ( shi ) and return temperature index ( rti ) can play an important role in the performance analysis of air distribution systems . in this research , by numerical modeling of a data center with soft ware , we compare four temperature indexes and performance estimation of subsurface air distribution system . then by changing the current status by proposed methods , the distribution of input and output temperatures to servers are compared and the most suitable ones are proposed

In this paper, Thermo-hydraulic behavior of flow in a heat exchanger pipe is investigated numerically and optimum geometry for the double perforated twisted tape turbulators and nano-fluid which produces the maximum thermal enhancement factor is determined. The analysis has been carried out for a flow range of Re= 10000 – 30000 and three different pitches with four different volume concentration of Al2O3 nano-fluid. Due to the twofold effect of turbulators on thermo-hydraulic behavior, thermal enhancement factor concepts are employed, which stands for both heat transfer rate and friction factor. Results show that maximum increase in Nu occurs at Re= 30000 and pitch ratio of 2.5 which is around 3% and the least increase occurs for pitch ratio of 4 at Re = 10000. The thermal enhancement factor decreases with increase of Re for all different pitch ratio and it is maximum value for pitch ration of 2.5, 3.25 and 4 are 1.72, 1.64 and 1.61 respectively. Also, thermal performance factor in creases with the increase of volume concentration of nanoparticles

The Lattice Boltzmann method (LBM) is employed to simulate heat transfer in flow past three arrangements of and horizontal and vertical rectangular obstacle under isothermal boundary condition. A thermal lattice Boltzmann BGK model is purposed to simulate the two dimensional forced convection for the governing parameters as Reynolds number, Re=100 and the Prandtl Number for laminar flow 𝑃𝑟=0.71. Pressure distributions, isotherms and streamlines were obtained. Vortex shedding maps are observed in detail for various cases and signified that lattice Boltzmann method can be effectively used to capture velocity fluctuations. The present results are in good agreement with existing experimental and numerical data.