Ali Heydari Articles List

Open Access Article

1 - Accuracy assessment of Ro 3rd order and CUSP dissipation schemes to analyze transonic flow around pitching airfoil using structured spring network
Ali Heydari

In this article, the unsteady transonic flow analysis with moving boundary is considered to compare dissipation schemes consist of: SCDS scheme, Ro 3rd order and CUSP methods. So that the unsteady, two-dimensional, non-viscous, compressible flow around an oscillating ai More

In this article, the unsteady transonic flow analysis with moving boundary is considered to compare dissipation schemes consist of: SCDS scheme, Ro 3rd order and CUSP methods. So that the unsteady, two-dimensional, non-viscous, compressible flow around an oscillating airfoil is investigated by solving Euler equations with adaptive grid network. To enhance the ability of moving grid network and prevent interference grids, linear springs are used in tangential and normal direction to the surface. Also the difference between the upwind (Ro) and the central difference CUSP dissipation scheme analysis is studied. The main problem, which occurs to the solution of equations as a result of the phenomenon of shock in central differences, is instability and non-continuity in the solution because of the lack of shock information. To solve the problem the artificial dissipation is used. In this way, the oscillating airfoil motion, the adaptive network and artificial dissipation are modeled. For validation, results are compared with experimental data. Finally, the numerical accuracy is checked. The results show that the of solving the CUSP scheme at the airfoil trailing edge and the shock capturing leads to better accuracy. Manuscript profile

Open Access Article

2 - Sock behavior study in flow around pitching airfoil in transonic regime
Ali Heydari

In this study, solution of unsteady flows with moving boundaries is considered. So that two dimensional inviscid unsteady and incompressible flow around an oscillating airfoil is investigated by solving Euler equation using structured adaptive grid network. An adaptive More

In this study, solution of unsteady flows with moving boundaries is considered. So that two dimensional inviscid unsteady and incompressible flow around an oscillating airfoil is investigated by solving Euler equation using structured adaptive grid network. An adaptive grid is produced using linear spring network, which can be attached to the surface of the object and modeled moving surface. The work initially focused on production of adaptive spring grid network and different state of adaptive grid production is investigated. After investigations of mesh and time step independency, the results are compare with experiments. Also, to show the advantages of structured adaptive grid network, the results are compared with unstructured adaptive grid network. The results show that use of adaptive structured network leads to increasing the speed of solution while maintaining the accuracy. Also it can be seen that in pitching airfoil, the shock behavior depends on the direction of movement, instant angle and mean angle of oscillation. Manuscript profile

Open Access Article

3 - Numerical Investigation of heat transfer in fire heater tube of the gas unit of Tehran Refinery
احد عابدینی علی حیدری

One of the most fundamental problems in the furnace and fire heaters control and maintain the temperature of the tube in allowed range. In this study, heat transfer in tubes of Tehran refinery gas unit heater is investigated numerically. Simulation of combustion furnace More

One of the most fundamental problems in the furnace and fire heaters control and maintain the temperature of the tube in allowed range. In this study, heat transfer in tubes of Tehran refinery gas unit heater is investigated numerically. Simulation of combustion furnace has done by FIHR software and modeling of fluid flow is done by commercial Fluent soft war so that the surface temperature of the pipe is obtained. The results show that with increasing combustion air up to 15% can reduce the surface temperature of pipes. In addition, reducing the fluid flow rate to the amount foreseen in the design process as well as increasing combustion air temperature leads to the higher surface temperature of pipes. Manuscript profile

Open Access Article

4 - The effect of oscillating flows on aerodynamic of two airfoils in tandem
Ali Heydari یزدان پیرحیاتی

In this study, two-dimensional oscillating flow around two airfoils in tandem is numerically simulated. With assuming unsteady, incompressible and viscous flow, the effect of oscillating amplitude and frequency on aerodynamic characteristics at different angle of attack More

In this study, two-dimensional oscillating flow around two airfoils in tandem is numerically simulated. With assuming unsteady, incompressible and viscous flow, the effect of oscillating amplitude and frequency on aerodynamic characteristics at different angle of attack is investigated. The Reynolds number is selected 11600 for SD7003 airfoil model and the distance between two airfoils equals to one chord. After mesh and time independency study, the results validation is done. The purpose of this work is to reach to the flight stability conditions in gusty and oscillating flows for biplane Micro Air Vehicles. To do this, the effect of amplitude and frequency of oscillating flow and the effect of interaction between two airfoils at different angles of attack must be investigated. The results show that increasing the frequency of inlet flow oscillation leads to reduction in lift and enhancement in drag coefficient in leading airfoil, but for trailing one, both the lift and drag coefficient will be increased. Manuscript profile

Open Access Article

5 - Development of solar air collectors for drying applications
Mohammad Mehdi Ebn Ali Ali Heydary

In this study, three types of solar air collectors (flat plate, finned, and v-corrugated) have been experimentally investigated in order to achieve an effective design which can be appropriate for a solar dryer. The experiments have been performed according to the ASHRA More

In this study, three types of solar air collectors (flat plate, finned, and v-corrugated) have been experimentally investigated in order to achieve an effective design which can be appropriate for a solar dryer. The experiments have been performed according to the ASHRAE standard and under real climatic conditions of Semnan (35° 33′ N, 53° 23′ E), Iran. Over a broad range of operating and design conditions, the performance of all three collectors have been studied. Based on the results, v-corrugated collector and flat plate one found to be the most and least efficient, respectively. Moreover, the collectors have also been studied in double pass mode in order to examined the extent in efficiency improvement. Manuscript profile

Open Access Article

6 - Entropy generation in a sample gas distribution network using steel and polyethylene pipes
Ali Heydari

Natural gas is extracted from wells and after purification, it reaches to consumption stages by transmission and distribution network. Energy losses in this section is vital and must be calculated appropriately. In this study, the network of distribution with low workin More

Natural gas is extracted from wells and after purification, it reaches to consumption stages by transmission and distribution network. Energy losses in this section is vital and must be calculated appropriately. In this study, the network of distribution with low working pressure is examined. A network sample of natural gas is investigated using analitical solution of a steady flow of natural gas. Flow equations initially provided for a tube considering all parameters. Then, using the existing rules in pipe networks the network sample is analyzed. Effect of tube material as an important factor on network performance are evaluated and analyzed And finally, the rate of entropy generation in steel and polyethylene pipes were compared. The results show that by increasing the diameter or decreasing the gas flow rate, the tube material and friction coefficient is less effective on entropy generation in practice. Furthermore, the gas flow in lower diameters cause more entropy production using steel pipes in compare with polyethylene pipes. Manuscript profile

Open Access Article

7 - Numerical Analysis of mixed conviction heat transfer for different nanofluids inside concentric annulus
سعید عمادالدین احد عابدینی علی حیدری

In this study, numerical mixed convection heat transfer in a horizontal concentric annulus in the presence of water-based fluid with nanoparticles of aluminum oxide, copper, silver and titanium dioxide discussed. Numerical solution using finite volume method based on SI More

In this study, numerical mixed convection heat transfer in a horizontal concentric annulus in the presence of water-based fluid with nanoparticles of aluminum oxide, copper, silver and titanium dioxide discussed. Numerical solution using finite volume method based on SIMPLE algorithm is done and discretization of equations generally is first order. Inner and outer cylinders have constant temperature and inner cylinder temperature is higher than outer one. Both of the cylinders can be rotated in either direction with constant angular velocity. The effect of parameters such as Rayleigh, Richardson, Reynolds number and volume fraction of nanoparticles on heat transfer and flow pattern discussed. Results showed that by increasing Rayleigh number increases heat transfer, heat transfer rate also increases with increasing volume fraction of nanoparticles and these increase is about 8.25 percent for 5 percent nanoparticles by volume. Rotation of cylinders reduces the overall heat transfer rate. Different rotation has large impact on the flow pattern and heat transfer. Adding nanoparticles has not significant impact on the flow patterns and isotherms but is effective in quantity. The results has good agreement with the similar work has been done before. Manuscript profile

Open Access Article

8 - Analysis of heat recovery from hot exhaust of gas turbines in compressed pressure Qazvin gas station
mahdi khajevand ali heydari mostafa mafi

In this study First, The heat recovery unit as an appropriate solution The energy savings will be introduced. Went on to study heat recovery from the hot exhaust gas compression facilities Qazvin And the waste of energy, The evacuation of hot gases through the exhaust f More

In this study First, The heat recovery unit as an appropriate solution The energy savings will be introduced. Went on to study heat recovery from the hot exhaust gas compression facilities Qazvin And the waste of energy, The evacuation of hot gases through the exhaust flue gas turbines on the environment has been determined For this work, according to data compression station Qazvin Aspen software with the help of the flow of energy in the hot gas exhaust flue Haysys first in both the max Simulation results show that for a unit of 50 MW to 90 MW of energy waste is near imum and minimum simulated turbine and heat removal capacity in both ‌Grdyd extraction. Dark The heat removal capacity is largely dependent on the flow rate and temperature of the exhaust gas Then, according to the existing proposals and as an example, heat generated from the hot exhaust gases from the chimney at a power plant generating steam used as the maximum speed turbine and turbine output parameters such as pressure and pump inlet temperature of heat recovery exchanger examined Placed. Manuscript profile

Open Access Article

9 - A review of numerical studies on solar stills to determine the effective parameters on heat and mass transfer and efficiency
Ali Heydari Pedram Aliakbari

In recent years, due to population growth and the reduction of water resources, the human has forced to sweeten brackish water. While this work takes energy and high costs. Thus, the scientists studied a lot about solar desalination and the factors influencing them. In More

In recent years, due to population growth and the reduction of water resources, the human has forced to sweeten brackish water. While this work takes energy and high costs. Thus, the scientists studied a lot about solar desalination and the factors influencing them. In this study, we tried to have a review on the literature of numerical simulation of solar desalination systems with Assumptions: laminar natural convection, heat and mass transfer using finite volume method which presented by researchers who have been working in this field. This research is prepared for researchers who interested in this subject or those who intend to get acquainted of solar desalination systems, to have an appropriate reference for specialized study. Manuscript profile

Open Access Article

10 - Experimental analysis of direct evaporative cooling in a rotating cylindrical channel
Ali Heydari وحید صحافی

Paying attention to using systems with higher efficiency in buildings is increasingly necessary due to high energy consumption in buildings and lack of energy sources. On the other hand, air conditioning systems and cooling equipment accounted for the largest percentage More

Paying attention to using systems with higher efficiency in buildings is increasingly necessary due to high energy consumption in buildings and lack of energy sources. On the other hand, air conditioning systems and cooling equipment accounted for the largest percentage of building energy consumption. In this study some changes in direct evaporative cooling has been performed to reduce energy and water consumptions. A rotary cylindrical channel is assumed instead of the fixed evaporating chamber. Thus the pump is eliminated and the heat transfer coefficient is enhanced due to rotational water flow. The results are evaluated by changing input parameters such as different input speeds and different rotational speeds. The energy analysis is done and the effects of input parameters are investigated on cooling capacity, dew point effective, coefficient of performance and exergy loss. Manuscript profile

Open Access Article

11 - A review on radiation heat transfer in gases based on quantum mechanics and heat transfer
mehrdad mesgarpour Ali Heydari seyfollah saddodin

Radiation heat transfer is one of the most important way to heat transfer. Almost 95 percent of heat transfer in the universe is radiation. Radiation heat transfer has basically different with other type of heat transfer. The radiation heat transfer have some special fe More

Radiation heat transfer is one of the most important way to heat transfer. Almost 95 percent of heat transfer in the universe is radiation. Radiation heat transfer has basically different with other type of heat transfer. The radiation heat transfer have some special feature. No need material to transfer and exist in any temperature above zero kelvin. Quantum mechanics can be describe a new horizon to explain sub atomic phenomena. It can also answer an old question that unsolved for many years. For example the concept of black body or gas radiation. In this study shown that the quantum mechanics is fundamental of radiation. Manuscript profile

Open Access Article

12 - Laminar flow modeling of different nano fluids around a flat plate fin for geometry optimization at the heat sink
seyyed mohammad javad taheri Ali Heydari

This paper presents a mathematical model for geometry optimization of a rectangular cross-section flat plate fin with application in calculating optimized width of a heat sink for different Nano fluids (Aluminum oxide, Silicon dioxide, Titanium dioxide, Copper oxide, Go More

This paper presents a mathematical model for geometry optimization of a rectangular cross-section flat plate fin with application in calculating optimized width of a heat sink for different Nano fluids (Aluminum oxide, Silicon dioxide, Titanium dioxide, Copper oxide, Gold, Copper, Diamond and Ferros oxide) with water as based fluid. Flow impinging on the fin is considered laminar. The effects of Reynolds number, volume fraction of nanoparticles, particle size, inlet velocity and different average temperature on the geometry optimization of the fin are investigated. A rectangular flat plate fin made from copper with higher thermal conductivity is used as the test case. Various Nano fluids with different volume fractions (0.005% to 0.1%) and different nanoparticle sizes (3×10-8 to 1×10-7 nanometer) are analyzed. In this analysis, as a basic assumption, the length of the fin is taken larger than the width and the fin volume is considered constant. Then, width of the fin will be optimized. The results indicated that the highest and the lowest optimized width is related to Gold and silicon dioxide nano fluids respectively. Increase in volume fraction, inlet velocity and temperature and decrease in nano particle size leads to optimized width enhancement. Manuscript profile

Open Access Article

13 - Literature Review carried out in the field of solar Air heater
Ali Heydari mikaeel Forati

To reduce energy sources, efforts are underway to optimize thermal processes around the world. Solar energy as an important source of renewable energy on Earth, with simple technology cause reduction in air pollution and saving the environment with less fossil fuels con More

To reduce energy sources, efforts are underway to optimize thermal processes around the world. Solar energy as an important source of renewable energy on Earth, with simple technology cause reduction in air pollution and saving the environment with less fossil fuels consumption for the future. One application of the solar energy is solar air heaters which different design is done for different application. To ensure the performance of energy systems, analysis of first and second laws of thermodynamics can be more useful to analyze processes undertaken within the system. Exergy is considered as a key concept and it is a fundamental concept of accessible energy. Solar air heaters can be based on its performance cycle was divided into two categories: active and passive. In passive systems mainly based on the difference in specific gravity of air, naturally flow of warm and cold air is formed. But in activated systems a forced convective air flow is derived with external component like fan. Manuscript profile

Open Access Article

14 - A review on thermal conductivity of material in different type
mehrdad mesgarpour Ali Heydari seyfollah saddodin

Thermal conductivity is one of the most important property of any type of materials. It’s shown that how much thermal energy can be cross inside the body. Solid material have the most rate of thermal conductivity. After solid material, fluid and gases have thermal More

Thermal conductivity is one of the most important property of any type of materials. It’s shown that how much thermal energy can be cross inside the body. Solid material have the most rate of thermal conductivity. After solid material, fluid and gases have thermal conductivity rate. Measuring this property is step 1 to understand where and how material can be use. In this study several ways to measure thermal conductivity is shown. Also for non-solid material like fluid and component material introduce some new experimental test to measure thermal conductivity Manuscript profile

Open Access Article

15 - An overview of the phenomenon through different scenarios in fluid mechanics and molecular transfer
mehrdad mesgarpour Ali Heydari seyfollah saddodin

Percolation is one of the most common phenomena in nature. For example water goes to ground or transport salt in reverse osmose. Many natural events or influence in the heat transfer, mass transfer issues have also been analyzed. With the advance of knowledge and enter More

Percolation is one of the most common phenomena in nature. For example water goes to ground or transport salt in reverse osmose. Many natural events or influence in the heat transfer, mass transfer issues have also been analyzed. With the advance of knowledge and enter into new areas, new issues emerge in the face of science. In this paper, the three main types of penetration, diffusion, mass diffusion and diffusion in the fluid will be discuses. The influence of molecular diffusion topics in molecular size and low displacements are often based on the concentration is investigated. The mass that occurs on a larger scale is usually different factors such as physical and environmental factors Manuscript profile

Open Access Article

16 - The principles of heat transfer and fluid mechanics in porous media (review)
mehrdad mesgarpour Ali Heydari seyfollah saddodin

Porous materials are encountered literally everywhere in everyday life, in technology, and in nature. With the exception of metals, some dense rocks, and some plastics, virtually all solid and semisolid materials are "porous" to varying degrees. There are many examples More

Porous materials are encountered literally everywhere in everyday life, in technology, and in nature. With the exception of metals, some dense rocks, and some plastics, virtually all solid and semisolid materials are "porous" to varying degrees. There are many examples of porous materials in everyday life and the environment. Textiles and leathers are highly porous; they owe their thermal insulating properties, as well as the property that they "breath ," to their pore structure. Paper towels and tissue paper are also highly porous; these owe their absorbency partly to their porous structure and partly to the property that they are strongly wetted by water. In this study, mathematical model and formula based on porous media will be discuses. Manuscript profile

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