Analytical study of the continuous regime effects of hydrogen-air mixture put into a micro-channel with platinum catalytic surface
sayyed Aboozar
Fanaee
Department of Mechanic, Facualty of Engineering, University of Birjand, Birjand, Iran
author
Mina
Rajaee
Deparment of Mechanics, University of Birjand
author
text
article
2019
per
In this paper, the analytical investigation of two thermal and mass transfer effects for non-homogeneous catalytic reaction mixture into a micro-channel has been achieved considering the continuous regime properties. In this problem, the Knudsen number is considered smaller than 0.1 where the flow is in the continuous or slip regime. The governing equations are consisting of energy, mole fraction and catalytic conversion where the wall effects have been achieved from thermal and mass jump boundary conditions. The solution results at three different values of Knudsen number are compared with experimental data, and at all points, when the Knudsen number is equal to 0.01 the best validity by experimental data be available. The results of slip-jump solution, with maximum error of 2.54%, has a better validated experimental values than based modeling data without slip and jump condition, with maximum error of 26.6%. The greatest increase in fuel conversion occurs at low-level Reynolds number, with a value about 80.04%. Increasing thermal jump effect coefficient, normalized temperature reduces while with increase in mass jump effect coefficient, fuel conversion decreases and surface mole fraction increases.
نشریه پژوهشی مهندسی مکانیک ایران
ISME
2538-4775
20
v.
4
no.
2019
6
25
http://jmep.isme.ir/article_34806_84807678708b7aee86328d65a2a05afc.pdf
Comparison of one-dimensional two-fluid models to predict two-phase gas-liquid flow variables in a vertical pipe and determination of an appropriate model
Vahid
Shokri
Department of Mechanical Engineering, Sari Branch, Islamic Azad University, Sari, Iran
author
Kazem
Esmaeili
Department of Mechanical Engineering, Sari Branch, Islamic Azad University, Sari, Iran
author
text
article
2019
per
In this paper, an approach to the prediction of two-phase flows based on two-fluid models and conservative shock capturing method is presented. The advantage of this approach is that the interface is allowed to develop naturally as part of the transient calculation. Another novelty is the comparison of well-posedness criteria of three two-fluid models and developmentation of the single-phase numerical approach to the two-phase numerical approach. The well-posedness criteria for single pressure model is greater than free pressure model, and the numerical diffusion for single pressure model is little than two pressure model. It has been chosen 0.0000001, 0.000001, 0.00001, 0.0001 and 0.001 for pressure relaxation term in two pressure model 1. It has shown that by increasing pressure relaxation, the result of the two pressure model 1 and two pressure model 2 tending two each other, and this is a Confirmation of equality of pressures in two-fluid model 2.
نشریه پژوهشی مهندسی مکانیک ایران
ISME
2538-4775
20
v.
4
no.
2019
26
53
http://jmep.isme.ir/article_34807_c1b5ec1855e717721c28c5b5097b98fa.pdf
Effects of nanofluids on the boiling-mode cooling of the engine
zahra
baniamerian
Assistant Professor, Department of Mechanical Engineering, Tafresh University, Tafresh, Iran,
author
Ramin
Mehdipour
Faculty of Mechanical Engineering, Tafresh University
author
text
article
2019
per
Abstract: Recent developments in automotive industry tend reseachers to design engines of lower volumes and higher efficiencies. Volume reduction enhances the generated heat per volume which in turn requires effective cooling methods to avoid thermal stresses on the engine walls. Nowadays nanofluids are extensively welcomed and employed as effective working fluids with efficient cooling potentials. Boiling phenomenon, by providing more amounts of heat transfer in comparison with single-phase, provides conditions for size reduction. In the present study effects of adding nanoparticles to the pure water as the cooling working fluid in the radiator is assessed. The employed nanoparticle is TiO2. A 3D model of engine with the cooling passages is simulated by CFD both for the pure fluid (water) and nanofluid. It will be shown employing 1 vol% TiO2 nanofluid improves cooling heat transfer up to 37% in comparison with the pure water. Keywords: Boiling mode heat transfe, Nanofluid, Engine, Cooling passages.
نشریه پژوهشی مهندسی مکانیک ایران
ISME
2538-4775
20
v.
4
no.
2019
54
77
http://jmep.isme.ir/article_34808_d8be6783acd13ea4ddc9ed9444d328bd.pdf
The effects of nanofluid in mixed heat transfer in localized ventilated with ventilation compartment
ALIREZA
SHEIBANI
pm
author
Seid Amir Abbas
Oloomi
Assistant Professor, Department of Mechanical Engineering, Yazd Branch, Islamic Azad University, Yazd, Iran
author
text
article
2019
per
Nanofluids are suspensions of nanoparticles in fluids that show significant enhancement of their properties at modest nanoparticle concentrations. Nano fluid is a smart fluid. The flow and heat transfer of a mixture of two different types of Nanofluids (water-alumina and water - copper oxide) in a localized ventilated compartment will be investigated by a finite volume method for three different situations. The results will be presented in the form of flow lines, constant temperature, and Nusselt numbers. Inlet fluid is at cold temperatures and walls with outlet ports in extreme conditions. The studied parameters include input fluid intensity (500≥Re≥100), Riley number effects (105≥Ra≥103), Nanofluid concentration (0.05≥ Φ ≥ 0). The numerical results show that, for example, in the first position, in Reynolds 100 and Riley 103 in pure water state, the mean Nusselt was as much as 7.7 and reached 8.61 in the concentration of 0.33. Which will increase by 17.78% to Nusselt.
نشریه پژوهشی مهندسی مکانیک ایران
ISME
2538-4775
20
v.
4
no.
2019
78
96
http://jmep.isme.ir/article_34810_b633122b51031a2833d1c8e4ffc61b9d.pdf
Evaluation the effect of smart glasses on solar heat gain and cooling loads in office building in hot and humid climate of Bushehr
jalil
shaeri
Faculty of art and architecture, Shiraz university
author
roza
vakilinazhad
Faculty of art and architecture, Shiraz university, Shiraz, Iran
author
text
article
2019
per
Today, application of advanced materials has made opportunities to reduce energy consumption of buildings and improve life’s quality. Smart glasses are among new materials designed to prevent energy loss through windows. Smart glasses could be categorized as Electrochromic glasses, liquid crystals, Gasochromics, Thermochromics and SPDs. In this article introducing various types of smart glasses, their characteristics and thermal performance had been compared. In order to evaluate the impact of smart glasses on energy consumption of building, a small office in Bushehr, Iran has been studied using Designbuilder simulation software. The results show advantages of using smart glass in reducing solar heat gain and cooling load of building. According to the results, SPD glass has the best performance reducing cooling load of building. Gasochromic, Electrochromic and Thermochromics glasses would also reduce the cooling load respectively. While the amount of solar heat gain varies in different months of the year, the average annual solar heat gain is the lowest using SPD glasses and Gasochromic, Thermochroic and Electrochromic glasses are in the next step. Application of SPD glass would result in 48.3% reduction in buildings cooling load compare to ordinary glass. The amount of reduction for Gasochromic, Electrochromic and Thermochromics glasses would be 45.8%, 34.1% and 17.23% respectively. So application of smart glasses in hot and humid climate of Bushehr can reduce solar heat gain and thus cooling load of buildings
نشریه پژوهشی مهندسی مکانیک ایران
ISME
2538-4775
20
v.
4
no.
2019
97
117
http://jmep.isme.ir/article_34811_6fbbba1e487a77c268ce52474ceb2d18.pdf
Design and Optimization of an Internal Combustion Engine Intercooler based on Genetic Algorithm
Tohid
Heydari
School of Automotive Engineering, Iran University of Science and Technology
author
Mohammad hasan
Shojaeefard
School of Automotive Engineering, Iran University of Science and Technology
author
Ali
Qasemian Moqadam
School of Automotive Engineering, Iran University of Science and Technology
author
Mohammad Mahdi
Niroobakhsh
School of Automotive Engineering, Iran University of Science and Technology
author
text
article
2019
per
Increasing the volumetric efficiency of internal combustion engines has always been one of the goals of the engine designers. Utilizing turbocharged systems is one of the common ways to achieve this aim. In these systems, compact heat exchangers are used to reduce the temperature and increase the density of the air at the outlet of compressor. This article seeks out the best geometric layout for an intercooler to have the lowest pressure drop and the highest temperature decrease of the passing air through the heat exchanger and at the same time leads to the lowest manufacturing cost. To obtain this purpose, a bar and plate heat exchanger is considered and after deriving all the geometric, flow and thermal equations, a comprehensive objective function is defined. Then, using the genetic algorithm method and considering six design variables, the best design values for variables are found to maximize the objective function. All calculations are done analytically and using coding in MATLAB software. The results show that the designed intercooler beside an appropriate weight and a very low pressure drop, reduce the engine inlet air temperature significantly and brings it to an acceptable level to enter the engine.
نشریه پژوهشی مهندسی مکانیک ایران
ISME
2538-4775
20
v.
4
no.
2019
118
136
http://jmep.isme.ir/article_35346_f4fbe98f7ef498bd86e0452e272514df.pdf
Experimental study of the effect of surface changes to reduce drag in a triangular array heat exchanger
Ali
Najaf Khani
Department of Mechanical Engineering, Islamic Azad University Central Tehran Branch, Tehran, Iran
author
آرش
میر عبد اله لواسانی
آزاد اسلامی تهران مرکزی
author
Mehdi
Zaki Zade
Department of Mechanical Engineering, Islamic Azad University Central Tehran Branch, Tehran, Iran
author
text
article
2019
per
The purpose of this study was to investigate the effect of surface changes to reduce the drag coefficient in a triangular array heat exchanger. Experiments were carried out in an open-circuit wind tunnel. The range of distance to diameter is between 2 to 4 and the Reynolds number is between 5.2×104 to 6.9×104. The diameter and length of the tubes are 41.5 mm and 42 cm, respectively. Tubes are made of copper. On each tube, 10 holes were created from zero to 180 degrees. The outer diameter of each hole is 3 millimeters.Shark skin is used as a surface accelerator. In these experiments, the effect of increasing the space ratio is studied. The results show that the coefficient of drag force decreases 14.5 to 25.4 percent for tube with shark skin. The greatest reduction in the drag coefficient is in Reynolds number 69920 and in the ratio of distance to diameter 2.
نشریه پژوهشی مهندسی مکانیک ایران
ISME
2538-4775
20
v.
4
no.
2019
137
153
http://jmep.isme.ir/article_34814_10b6895c4c2acf723143bd99a58cd1c2.pdf
Potential Analysis of the combination of two types of thermal and member of desalination unit in converting a gas power plant into Combined Water and Power (CWP)
Majid
Amiralipour
university of guilan
author
رامین
کوهی کمالی
گیلان*مهندسی مکانیک
author
text
article
2019
per
In this paper, a combination of a gas turbine unit with thermal and membrane desalination are evaluated technically and economically. A V94.2 Siemens gas turbine model with capacity of 150MV is selected for power generation.This system benefits by thermal and membrane desalination that work simultaneously. So that, preheated water of condenser in thermal unit is used as feed water into the membrane unit. By this combination, the desalted water is divided between thermal and membrane units. After modeling process, economical analysis has been performed and the cost of produced water In each of unit is calculated. As a benefit of converting gas unit into Water and power cogeneration system in this analysis due to the design of the system, the cost of water by thermal and membrane unit are calculated in 0.7,-1.45 dollars Per cubic meter Respectively. Finally, a parametric analysis due to the main indicators of power plants on modeling system is performed and by two-objective optimization and by considering of a gas power plant efficiency and also the capacity of desalination, an optimized condition of this combination is proposed.
نشریه پژوهشی مهندسی مکانیک ایران
ISME
2538-4775
20
v.
4
no.
2019
154
181
http://jmep.isme.ir/article_34813_a49a435cb8dc3e7a80a034d6aae6d967.pdf
Numerical investigation of flow separation control in an axial compressor cascade by plasma actuation
Amin
Kadivar
University of Guilan, Faculty of engineering
author
Nima
Amanifard
University of Guilan, Faculty of engineering
author
Hamed
Mohaddes Deylami
University of Guilan, Faculty of engineering, East of Guilan
author
text
article
2019
per
Interest in plasma actuator as an active flow control has grown rapidly in the last years. Plasma actuator consists of a pair of electrodes that are separated by a dielectric material. Applying voltage to the electrodes, results in a body force that act on the flow field and is used in order to control it. Plasma actuator by imparting momentum is able to tangentially accelerate the flow field that can be used for flow control purpose such as boundary layer transition control, drag reduction, lift enhancement, and flow separation control. This work involves the documentation and control of leading-edge separation control that occurs on an axial compressor cascade at high angle of attack. To study the effect of control technique, a 2-D numerical investigation were performed in presence of varying plasma actuator voltage and location in different flow characteristics such as stream line, pressure and lift-to-drag ratio. The results show that plasma actuator reduce energy losses and a lift-to-drag ratio enhanced of up to 18% can be obtain by using plasma actuator at 15% of the blade chord length. The control effect obtain by the plasma actuator in low Reynolds number is more effective and Increasing the applied voltage improves the performance of the compressor cascade by increasing the induced body force.
نشریه پژوهشی مهندسی مکانیک ایران
ISME
2538-4775
20
v.
4
no.
2019
182
209
http://jmep.isme.ir/article_34815_236d97e9a9b0654dae66c9f16540865e.pdf
Exact Solution of Viscous Fluid Velocity and Pressure Due to Kinematic Effect of Two-Dimensional Boundary Propagating Wave
Mohammad Ehsan
Khodaei Meidanshah
Department of Mechanical Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran
author
Khosro
Naderan Tahan
Department of Mechanical Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran
author
Mojtaba
Dehghan Manshadi
Department of Mechanical and Aerospace Engineering, Malek-Ashtar University of Technology, Isfahan, Iran
author
Amin
Yaghootian
Department of Mechanical Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran
author
text
article
2019
per
In the present study, to extend the Stokes' second problem, the bottom edge of viscous incompressible semi-space resting fluid is excited in two dimension, simultaneously. This two-dimensional excitation which is the effect of velocity of two-dimensional travelling wave, is boundary condition for the two-dimensional linear Navier-Stokes equations. The time-space exact solution for fluid velocity and pressure show that the amplitude of oscillating velocity has fast damping in space till 1.87 micron from excited surface. After this height, the amplitude of oscillating quantities has a slowly damping. In the first region (in fast damping region), phase difference between pressure and velocity is changing, but after that there is a region with constant phase difference. The space variation in velocity components of surface wave, together with the coupling of velocity components in main equations, produces pressure wave. It has been found that kinematic effect of vertical and horizontal harmonic motion cause damped rotational motion in fluid.
نشریه پژوهشی مهندسی مکانیک ایران
ISME
2538-4775
20
v.
4
no.
2019
210
233
http://jmep.isme.ir/article_34816_7b949db63c5040f42c286b5886973f13.pdf