R. Mehdipour

Tafresh University · Department of Mechanical Engineering

Solar energy is one of the most feasible options to produce energy in countries where unexploited desert areas or solar radiation are abundant. An energy tower is an effective system for electrical power generation that can perform more efficiently along with solar radiation. in this study, the efficiency of the energy tower system is investigated...

A novel combination of a conventional combined power plant and low‐temperature power generators as a cogeneration cycle coupled with a biomass gasifier is presented in this study. For this purpose, mathematical modeling of ORC, Kalina, and Goswami cycles was performed as a bottoming power system. To achieve the goals of sustainable energy developme...

In this study, effect of solar irradiation and suction head on an indirect cabinet solar dryer performance is investigated experimentally and numerically. In this regard, a specific experimental apparatus consisting a collector, heaters and adjustable chimney is fabricated to measure the air flow velocity and temperature at collector outlet in vari...

One of the best and most important types of concentrating solar power plants is the linear Fresnel collector. The thermal performance and application of absorber in a solar power plant can be enhanced using direct steam generation technology. A particular discrepancy between the present study and others lies in our attempt at applying a new method...

The collector in the solar chimney, in addition to absorbing solar energy, is responsible for collecting air and directing it to the chimney. Heat transfer occurs naturally and slowly through most of the chimney height which results in the formation of secondary flows that reverse the flow and cause losses in the entrance. In the present study, it...

Environmental pollution caused by burning fossil fuels, global warming, the greenhouse effect, and other factors has changed the approach of science to the use renewable energies. The main objective of this paper is to study the effects of diverse inputs (solar radiation) and collector geometries and also heat transfer of the solar chimney power pl...

During the hot seasons, the balance between power generation and consumption is disrupted due to the higher demand for cooling load and the lower power plant efficiency occurred due to the enhanced temperature of the inlet air to the turbine. The costly cold storage method in consumption centers (residential or official) is usually suggested to ove...

Besides meeting the ever increasing energy demand, renewable energy source can play a critical role in reducing global carbon emissions and the pace of investment on such renewable energy has greatly increased as the cost of technologies fall and efficiency continues to rise. However, the benefits of renewables go beyond reducing carbon emissions a...

Automotive industries are constantly seeking to produce more powerful and efficient engines. One of the factors affecting engine efficiency is the engine's temperature. Several research studies have been done to control and reduce engine temperature. The generated heat due to combustion of fuel in the engine should be cooled down to avoid engine he...

Utilization of direct steam generation is a significant point in the solar power plants particularly in linear Fresnel collectors. In this research, the increased heat transfer coefficient has been scrutinized in the used nanoparticles with volumetric concentrations of 0.01 to 2% in comparison with pure water in the linear Fresnel collectors for tw...

Power generation of solar chimneys effectively depends on their thermal performance. The manufactured samples, available in the literature, have many functional weaknesses and their obtained output power is much lower than expected. Due to the variation of operating conditions (i.e. solar radiation, wind velocity, ambient temperature etc.) of outdo...

With conventional water sources in short and decreasing availability, new technologies for water supply have an essential role to play in addressing the world's clean water needs in the 21st century. In this paper, we show how nanometer-scale pores can excellently filter NaCl salt from water. Using classical molecular dynamics, we show the relation...

In this paper heat transfer and critical heat flux is investigated in the Linear Fresnel Collector. At first, the balance of energy in the absorber was used for the modeling of direct steam generation in the Fresnel solar plant. In the following, thermal analysis has been executed in three different mass flow rates and single and dual tubes. Eventu...

The hybrid solar chimneys power plant can produce electric energy and fresh water simultaneously. The purpose of this research is to numerically analyze the hybrid solar power plant, using heat transfer mathematical models. In this study, performance of two different cases for power generation are investigated. First, combination of solar chimney a...

In this study, an advanced combined power generation cycle was evaluated to obtain sustainable energy with high power and efficiency. This combined cycle includes biomass gasification, the Cascaded Humidified Advanced Turbine (CHAT), and the steam turbine. The fuel consumed by the system is derived from the gas produced in the biomass gasification...

Free download link (50 days): https://authors.elsevier.com/c/1ZgIX6gYtN6RJ3 Aeolian particle transport involves uplift from the ground, dispersion and deposition back to the surface. Integrated effects of these processes, in general, are of great importance for a wide range of reasons mostly because of their unwanted deposition on the railway tra...

This paper is devoted to measurement and prediction of the saturated flow boiling of nanofluids. In this regard, pressure–temperature variations at saturation conditions are experimentally investigated for different types of water-based nanofluids with variable volume fractions of nanoparticles. By using measured saturation temperature/pressure dat...

Advanced combined cycles using gas turbine and bottoming cycles have been developed to improve energy efficiency and output power of the conventional thermal power plants. In this study, integrated biomass gasification‐cascaded humidification advanced turbine and steam turbine cycle have been presented as a novel approach to reach out the sustainab...

In the solar parabolic trough collectors, functioning based on direct steam generation system, heat transfer system and appropriate thermal stress are indicated as two most important thermal parameters. High amount of the critical heat flux creates an extensive application range for the system so heat transfer systems can function without being sub...

Today, solar parabolic trough collectors are the most appropriate 6 technologies in solar power generation due to higher efficiencies in comparison 7 with other collector types. In this paper, a numerical heat transfer model is 8 considered, for simulation of this equipment. The inlet heat flux to the absorber 9 is calculated to be considered as a...

Utilization of direct steam generation (DSG) is a culmination point in the solar power plants with parabolic trough collectors. For these systems that working temperatures commonly exceeds 400 °C, while thermal oils cannot be employed due to inflammability dangers and thermal stability issues, water is used as the working fluid. Great heat transfer...

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...

Today, solar parabolic trough collectors are the most appropriate technologies in solar power generation due to higher efficiencies in comparison with other collector types. In this paper, a numerical heat transfer model is considered, for simulation of this equipment. The inlet heat flux to the absorber is calculated to be considered as boundary c...

Article info: Abstract Solar chimney power plants are solar thermal power based plants, including three parts of collector, chimney, and turbine, which are able to produce electrical energy. One of the effective parameters in increasing the power production is the collector angles versus horizon. In the present study, a numerical analysis of a sola...

Cascaded Humidification Advanced Turbine (CHAT) cycles have been proposed to increase delivered power of simple gas turbine systems. In this paper, an Integrated Biomass Gasification (IBG)-CHAT-Steam Turbine (ST) combined cycle has been presented as a novel approach to consider the restrictions of power generation in gas turbine (GT) systems using...

The aim of this study is to determine the optimum location to install a wind turbine in a mountainous terrain using computational fluid dynamics (CFD). This aim is achieved with the use of inverse methods, with the objective of maximizing the efficiency of the turbines while minimizing loss expenses caused by placing them in a less optimum area. On...

Paint cure oven as one of the most important instruments in production lines involves with many key parameters like curing rate and energy consumption. Radiation paint cure ovens usually have smaller amount of energy consumption beside providing better curing conditions and as a result, attracts attentions of many manufacturers. Designing this type...

Hybrid nanofluids are novel fluids that can be prepared by suspending various kinds of nanoparticles in a base fluid. In this paper, various syntheses of Au with Ag, TiO2, Al, and Ni nanoparticles are prepared and employed in some sets of experiments to investigate effects of pressure and nanoparticle type and concentration on heat of evaporation o...

This paper concentrates on a new procedure which experimentally recognises gears and bearings faults of a typical gearbox system using a least square support vector machine (LSSVM). Two wavelet selection criteria Maximum Energy to Shannon Entropy ratio and Maximum Relative Wavelet Energy are used and compared to select an appropriate wavelet for fe...

Movement of sand particles in nature creates many problems for humans. One of these problems is deposition of particles on rails that decreases the speed of the train or in some cases hampers the reversal of the train rails. In this paper, the motion of sand particles over railway track embankment, and how these particles settle on railway tracks a...

An accurate knowledge of heat transfer and temperature distribution in vehicle engines is essential to have a good management of heat transfer performance in combustion engines. This may be achieved by numerical simulation of flow through the engine cooling passages; but the task becomes particularly challenging when boiling occurs. Neglecting two...

Recently, increase in the cost of fossil fuels and taking into consideration the environmental effects of exploiting them, caused many researchers and governments to find some ways to make use of renewable energies more cost-effectively. Solar energy is a category of renewable energies which could be harvested via several technologies. One of the m...

In this study, a new approach for numerically modeling of an entire cabinet solar dryer is proposed. Collector, drying chamber and chimney are the three principle sections considered in the present modeling. The collector section containing a cover and an absorber plate is modeled applying energy and fluid flow equations to obtain temperature distr...

Paint cure oven is one of the most important parts of automobile production line. The cure speed and the magnitude of energy consumption are significant in auto manufacturing industry. The radiation oven has been of the interest by cure industry due to the reduction in energy consumption and appropriate cure. The design process of these ovens is re...

In the present study a non-Newtonian fluid flowing in an annulus pipe, has been simulated numerically. The considered geometry is an annulus pipe equipped with some fins. Heat transfer and entropy generation for some different fin geometries have been characterized through a written computer program. The written code is based on finite element meth...

Shrinking the engine has been a great interest for many years. Providing more amount of heat transfer may supply possibilities for size reduction in engine parts specifically the engine water jacket that is of concentration for the present study. Boiling phenomenon, by providing more amounts of heat transfer in comparison with single-phase, provide...

The pressure drop, heat transfer and dryout characteristics of five different refrigerants in a 1-cm-diam tube are numerically investigated using a novel approach to model the mass transfer associated with ebullition in the liquid film using computational fluid dynamics. The four different mass transfer mechanisms, namely, entrainment, deposition,...

The wind makes the drag and lift forces to sand and gravel particles. These forces cause movement of sand particles in a gas-solid phase. In recent years, the issue of sand movement particles has been one of the main problems of Iran, especially in the southern and southwestern region. The first step in analyzing these phenomena and looking at the...

Over time, sand dunes have been formed by climate change and erosion phenomenon in the desert. In this paper, we study temperature and thermophoresis variations in day and night, and how they affect the movement of particles from a sand dune. It is observed that the maximum velocity of the sand particles is much higher at night than of the same day...

Movement of sand particles creates many problems in the environment. In this study, we investigate the 2D motion of sand particles for porosities of 20 and 50 percent. Filters change the direction of the sand particles. Therefore, after that, these particles move regularly and velocity decrease. Decrease the sand particles velocity is higher for po...

Sand dunes have been formed due to the movement of sand particles and the phenomenon of wind erosion in the desert over time. In this paper, we investigate the 2D motion of sand particles from the sand dune. In nature, the density of sand particles in the stream flow air is significant, but behind the dune is low. The velocity of sand particles is...

One of the significant factors in the motion of sand is a wind which causes to drag (horizontal), Magnus (rotational) and lift Safman forces to sand particles. The sand particles move with the respect of environmental conditions. In this paper, we investigate the 2D motion of sand particles and consider the advantages of using the filter. Filters c...

In most types of industrial processes, heat exchangers play an important role in cooling functions. The effective heat transfer rate in a specific process strongly depends on heat exchanger performance. The most popular type of heat exchangers commonly used in automotive industry, is called radiator. In most types of engine processes in vehicles, r...

In the present study, a numerical model is developed for simulation of annular two-phase flow considering bubbly flow regime in the liquid film along with the four involved mechanisms of mass transfer those are evaporation, entrainment, deposition and condensation. In the numerical approach, liquid film accompanied by fine nucleated bubbles are sim...

Efficiently employing two-phase flows for cooling objectives requires comprehensive knowledge of their behavior in different conditions. Models, capable of predicting heat transfer and fluid flow trends in this area, are of great values. Numerical/analytical models in the literature are one-dimensional models involving with many simplifying assumpt...

Continuous paint cure ovens have many important industrial applications. In particular, convection ovens are extensively used in auto industries. Radiation paint cure ovens have attractive features as well and attempts have been made to design the oven and the radiation panels such that the moving loads experience desirable, nearly uniform, heating...

Purpose The purpose of this paper is to model radiation ovens and to propose a method capable of designing this kind of oven for the paint curing application. Providing a uniform cure condition on the body, especially bodies of complicated geometries, needs accurately‐designed ovens. An algorithm with high speed and high convergence capability is t...

Having more heat transfer rate and lower pressure drop, along with better environmental treatment, carbon dioxide has drawn the attention of many researchers. Most of the two-phase heat transfer analyses are involved in estimation of dry-out phenomenon in order to avoid heat transfer drops. Entrainment, because of having great influence on dry-out...

Ever increasing demands for high-efficiency cooling systems have tended many researchers to apply two-phase flows for cooling objectives. Two phase flows in compare with those of single phase bring about considerably more amount of heat transfer. However, unstudied applying of these flows may result in some troubles like dry out that is accompanied...

Providing a suitable thermal condition for the paint to be cured is of important parameters in achieving a desired cure. Continuous radiation ovens are of widely used apparatuses in paint cure and coating industries. Designing of these ovens for curing bodies of complex geometries have become a challenge for many years. In the present study a desig...

Radiation ovens are gaining popularity in paint curing due to the ease of thermal control and the possibility of having a dust-free environment around the painted body as it dries. In this article a thermal analysis of paint curing is presented and two dynamic gradient-based optimization algorithms are used to design the radiation panels in a paint...

Complex heat transfer phenomena occur in auto paint curing ovens. Due to the complexities in the geometry, boundary conditions and the heat and fluid flow fields, analysis of the heat exchange and the curing process is difficult and numerical simulation is urgently needed. However, development of a computationally affordable yet sufficiently accura...