هادی کارگر شریف آباد

In the present research, the behavior and flow pattern of a Counter-current Gas-Liquid Two-Phase Flow in Transparent Vertical pipe made from Plexiglas with inner diameter of 38 mm was experimentally investigated. The considered fluids included the water and the air, and the results were obtained for a total of 125 select cases differing in the apparent velocities of the water and the air. The supperfacial velocities of the air and water in the 38 mm pipe were investigated in the ranges 4.90 – 9.30 m/s and 0.083– 0.139 m/s, respectively. The Entrainment fraction was measured Isokinetic-sampling technique. Provision of the Counter current Gas-Liquid Two-Phase Flow conditions in terms of initial flow orientation and the investigation of the effect of this design on the flow patterns, liquid film thickness, and the Entrainment fraction are the major innovations of the present research.In contrast to previous research works, the present study sets the scene for a more accurate evaluation of the annular flow pattern for calculating the liquid film thickness and the Entrainment fraction by designing the initial inlet orientation. Based on a comparison, as far as the calculation of the Entrainment was concerned, the results of the present research exhibited good agreement with the Wallis model in the 38 mm pipe, and when it came to obtaining the liquid film thickness, the results were consistented to those of the Schubring model.It is shown that the predictions of this new correlation outperform those from previously reported studies.

Nanofluids have been highly interested by researchers based on their interesting thermophysical properties and application in important branches of engineering such as heat transfer. However, there are contradictions in the laboratory results and the topics presented in several cases such as effective heat conduction, convection heat transfer coefficient and boiling heat transfer rate. In contrast to convective heat transfer, limited efforts have been made in boiling nanofluids. However, to exploit nanofluids as the next generation of coolants, boiling research is essential. The boiling process in magnetic fluids (a class of nanofluids with magnetic nanoparticles, mainly iron), in addition to showing the general characteristics of the boiling of nanofluids, is remarkable due to its ability to be controlled by the application of a magnetic field.

Phase change materials are increasingly playing an important role as heat transfer fluids and energy storage sources. This is a new technology in the field of thermal energy storage using phase change materials. In this article, the properties of microcapsules of phase change materials are studied and some widely used materials as core and shell materials were presented. Also, some of the uses of these materials are briefly mentioned. In the following, the method of manufacturing microcapsules based on n-octadecane and silica shell and microcapsule of phase change material with melamine core and formaldehyde shell is discussed.

In the present research, the behavior and flow pattern of a Counter current Gas-Liquid Two-Phase Flow in different Transparent Vertical pipes made from Plexiglas with inner diameters of 26 mm and 44 mm were experimentally investigated. The considered fluids included the water and the air, and the results were obtained for a total of 304 select cases differing in the apparent velocities of the water and the air. The air and the water were flown from separate inlets upward and downward, respectively. The apparent velocities of the air and water in the 26 mm pipe were investigated in the ranges of 10.47 – 26.17 m/s and 0.06 – 0.36 m/s, respectively. The corresponding ranges for the 44 mm pipe were  3.56 – 9.14 m/s and 0.02 – 0.12 m/s, respectively. The liquid film thickness in the annular flow was measured by the Quick shut valve technique. The Entrainment fraction was measured Isokinetic-sampling technique. Provision of the Counter current Gas-Liquid Two-Phase Flow conditions in terms of initial flow orientation and the investigation of the effect of this design on the flow patterns, liquid film thickness, and the Entrainment fraction are the major innovations of the present research.In contrast to previous research works, the present study sets the scene for a more accurate evaluation of the annular flow pattern for calculating the liquid film thickness and the Entrainment fraction by designing the initial inlet orientation. Based on a comparison, as far as the calculation of the Entrainment was concerned, the results of the present research exhibited good agreement with the Oliemans model in the 26 mm pipe and the Wallis model in the 44 mm pipe, and when it came to obtaining the liquid film thickness, the results were consistented to those of the Schubring model.It is shown that the predictions of this new correlation outperform those from previously reported studies.

The process of roomchr('39')s air-conditioning system is used to enhance thermal comfort and to reduce energy consumption. Although most of the researches have concentrated more on flow rate and optimum temperature of inlet air, the present study software was used to obtain the best possible locations for inlet and outlet channels for 20 samples of room using Ansys Fluent. Three factors including ventilation efficiency, effective average temperature, and vertical temperature gradient were considered to find the best location for inlet and outlet port locations. As a result, model 20, where inlet channel placed in the middle of opposite wall from manikin and the outlet channel located at the bottom of the same wall, was approved. In this sample, the average temperature was 23.68; the ventilation efficiency was 2.36; and the average effective temperature was -1.01. Moreover, the analysis of rooms with area of 12 𝑚2, 16 𝑚2, and 20 𝑚2 showed that by increasing the area, the ventilation efficiency decreased by 11.86%, and by increasing the air flow from 0.045 to 0.134 m3/s, the average temperature room decreases 12.54%.

One of the most important issues in the world today is energy saving, which in the construction industry, proper thermal insulation is one of the solutions to prevent energy loss. Also, the use of new and suitable insulation materials helps us to achieve this. Energy crisis, global warming and other environmental issues have always been the main motivation for researchers and engineers to look for new ways to reduce building energy consumption. Recently, the use of phase change materials to increase the thermal mass of the building has received much attention. Phase changers are organic or inorganic compounds that have the ability to absorb and store large amounts of heat energy within themselves. Due to this unique feature, using these materials can naturally delay the transfer of heat to the building for several hours during peak hours of energy consumption and therefore closer to the goal of optimizing energy consumption in the building. The use of phase change materials in the construction industry along with the proper use of the capabilities and physical properties of materials, was introduced in the world several decades ago and is now known in developed countries, while in our country the research and application of these materials in the construction industry remains almost unknown. The purpose of this article is to introduce and provide suggestions for using phase change materials to store and reduce energy consumption in the building.

In this experimental study, the forced convection heat transfer of thermally developing Fe2O3/water nanoparticles inside a copper tube under magnetic field created by a number of permanent flat magnets is investigated. Experiments have been carried out under laminar flow regime and uniform heat flux boundary condition and the influence of magnetic field position and intensity. The objectives of this study were to investigate the effect of using Fe2O3/water nanofluid, flow Reynolds number, intensity and magnetic field position on the thermal behavior of the flow. Validation of the test apparatus was performed using distilled water and compared with the theoretical results, which eventually achieved good agreement. The results show that due to the influence of the magnetic field on the Fe2O3/water nanofluid, secondary flow and boundary layer deformation occur, the heat transfer changes and its variation is dependent on the flow profile and intensity and position of the magnetic field. Increasing the intensity of the magnetic field perpendicular to the flow at a single point in the constant Reynolds causes a sudden increase in the local convection heat transfer coefficient but the mean convection heat transfer coefficient in the latter case is higher than in the former case.

Energy saving is one of the challenges of today. In recent years, growing concerns about the environmental impacts of energy consumption and global warming has doubled the importance of this issue. Meanwhile energy consumption in construction sector is so high that saving even as little as possible in this section will have significant effect on efficiency rate of no renewable sources. Accurate measurement of thermal conductivity has an important role in determining the calculations of cooling and heating loads of buildings according to different climates. Considering multiple relevant parameters in energy consumption with no application of simulating tools cannot permit reasonable decisions on designing building parts. In this research, the annual energy consumption of an office building located in the climate of Yazd city has been simulated and compared by Design Builder.

Reducing fossil energy resources, the environmental impact of high energy consumption and increasing the energy consumption in the building section, has increased the importance of attention to building energy consumption in the country. Providing the standard of building energy consumption in our country is one of the important activities in this regard. This study aimed to determine the effect of different strategies to reduce energy consumption in the energy classification of office buildings as a case study by Design Builder software.

In this study, the total energy consumption of of an office building in Semnan climate was simulated by Design Builder software and the results obtained by the software, with the actual energy consumption of the building in 2016, which was obtained from the energy bills (electricity and gas) of the building, were validated. Then, using the energy rating of building, different strategies for reducing energy consumption were simulated and compared with the existing situation.

Using energy simulation software, various energy efficiency strategies such as using external horizontal shading and removing internal shading, replacing windows with low-emitting double-glazed windows instead of single-glass windows and installing a thermal insulation in the external wall of the building were investigated that 15.2, 18.4 and 8.2% reduction in energy consumption achived compared to normal case, respectively. Then, the intensity of building energy consumption for each of the proposed strategies were calculated and the energy rating was determined for each.

The results showed that the replacement of external shading instead of internal shading had the least amount of savings and had no effect on the change in energy rating and the use of a combination of double glazing instead of single-walled and thermal insulation in the outer wall of the building while upgrading to the classification, the optimal suggested mode. Finally, the results of this study showed that in the case of accurate simulation of existing buildings and then validation the effects of different strategies on energy rating and consumption can be predicted accurately.

Due to the fresh water shortage crisis in all around the world, many types of desalination systems have been developed. One of the most used type of them is solar desalination system. In this paper, a parametric study has been employed for investigation of the effects of mounting a normal and porous fin on the heat transfer and water production rates of solar still desalination. A fin with different porous intensity in different positions has been put in solar desalination. For modelling the mentioned desalination, the desalination geometry has been meshed and the 3D simulation has been performed using ANSYS Fluent software. As the result of simulation, putting fin in optimum position in a solar still desalination leads to considerable increment of Nusselt number which results in increase of mass transfer and fresh water production rates. In addition, employment of porous fin will cause decrease in heat transfer and mass transfer rates. Finally, the effects of adding fin on the vortexes in the desalinator and its impacts on temperature and mass fractions differences in various zones has been also examined.

One of the most important ways to manage consumption is to reduce non-revenue water and losses in urban and rural water supply systems. The inaccuracy of the meters can have direct impact on the evaluation of loss water control programs as well as resource conservation programs thereby leading to incorrect decisions. In this paper, for numerical simulation of the effect of direct pump installation on the performance of domestic water meters, a turbine water meter of multi-jet production type is selected. It is assumed that the values of the mechanical brake torque on the impeller, such as the bearing friction drag torque, and magnetic magnitude is insignificant and can be considered as zero. The input and output flow are the fully developed in the water meter where K-ω-SST turbulent model is selected and the rotational speed of the impeller is collected at different flow rates. Comparing the numerical solution results with the manufacturer's practical experiments data, reveals the maximum error of 9.66%. Thus, the model can be used to evaluate the effect of direct pump installation on the performance of domestic water meters. As a real-world case, the water meter performance when the centrifuge pump is directly inserted into the outlet of the water meter is simulated and the results were compared with the non-pumped state. the behavior of the water meter when the pump is installed at the outlet of the water meter differs from the non-pumped mode in different flow rates. This difference is due to the change in the flow profile and the angle of impact of the water with the impeller. The results indicate that in high flow rates (more than 536 L/h) with the other same conditions, rotational speed of the impeller is less than the non-pumped state with the maximum decrease of 17% and thus the meter has a negative error measurement. However, in low flow rates (less than 75 L/h) the rotational speed of the impeller is increased almost twice more than the non-pumped state causing enlargement in meter's orders of error measurement.

The heat pipe as superconductors can play an essential role in heat transfer According to the application, are designed in different sizes The heat pipe for heat transfer with very high thermal conductivity that heat energy by evaporation and condensation of a working fluid with minimal temperature drop pass When the heat of evaporation area is the working fluid evaporates and creates a pressure gradient in the tube The steam pressure gradient along the tube makes the move to steam condenser condenses in the condenser is, the latent heat is released. The working fluid of the heat pipe by gravity thermosyphon returns to the evaporation zone In this study the vapor and liquid inside the heat pipe is modeled thermosyphon type It is assumed that the flow is permanent and peaceful two-dimensional and volumetric forces have been ignored. In this paper, the finite volume method and SIMPLE algorithm is used. The geometry of the model with the software Gambit drawing grid and numerical calculations to using a software package Efficient called Ansys Fluent by subsidies carried out and the results with the results of a study comparing the temperature of the wall and the heat pipe in all three areas have been analyzed.

In this paper the forced convection of Cu and Fe3O4 and Cu/Fe3O4 hybrid nanofluid in the laminar regime under constant heat flux codition is investigated experimentally. Experiments are carried out in three volume fractions of 1, 2, 4 % and three Re number of 600, 1200 and 1800, and local Nusselt number is measured. The results show that for nanofluid in simple and hybrid mode, with increasing the volume fraction of nanoparticles and Re number, the heat transfer coefficient is increased. results revealed that the heat transfer rate is augmented for both cases of simple and hybrid nanofluids with a rise in the particle volume fractions or the Re number. In addition, the comparison of the experimental data of Cu, Fe3O4 and hybrid nanofluids indicated that the heat transfer enhancement is more remarkable in the case of hybrid nanofluid. In the case of Cu/Water nanofluid, the greatest increase in the heat transfer vs. pure Water is 7.8% and in the hybrid nanofluid 11.9%. Also, the volume fraction of hybrid nanofluids is very effective in increasing the coefficient of heat transfer, so that in a 2% volume state, an increase is observed over other simple nanofluid volumetric fraction.

One of modern world challenges is saving energy consumption. Multiple increase in energy price on one hand and limitation of fossil fuel as well as its consequent bio environmental pollution on the other hand have shown the necessity of sensible energy application. Meanwhile energy consumption in construction sector is so high that saving even as little as possible in this section will have significant effect on efficiency rate of no renewable sources. Considering multiple relevant parameters in energy consumption with no application of simulating tools cannot permit reasonable decisions on designing building parts. In this research the proportion of annual energy consumption of office building located in Semnan city climate with application of design builder software has been simulated. Accuracy of results from simulation has been validated with recorded numbers at annual electricity and gas bills at the building.

In today's world, the national security of most countries has depended on secure energy access, and therefore the optimum use of it has been the focus of attention of many statesmen and researchers. Expansion of consumption in the household sector and waste of energy in the urban community are among the obvious reasons for the rapid growth of energy consumption in the national economy. For this reason, energy consumption in the building sector needs to be considered. In this paper, after simulating an office building in Garmsar City with Design-Builder Software and validating it, the effect of the roof insulation and double wall parameters on the energy consumption has been investigated. The results show that the roof insulation and the use of a double wall can have a significant impact on building energy consumption.

In this paper, the energy and exergy of single effect absorption and combined ejector-absorption refrigeration cycles are carried out analytically. Having analyzed the cycles and presented the governing equations with their expansion in EES software, we analyze the energy and exergy (from the viewpoint of the first and second law of thermodynamics) of both single effect absorption and combined ejector-absorption refrigeration cycles (while the ejector is located between the condenser and the generator) and calculate the value of output variables. Furthermore, the effects of evaporator and generator temperature on irreversibility, coefficient of performance, exergy loss and exergy efficiency of the aforementioned cycles have been investigated. We observe that, under identical conditions (i.e. equal temperature of evaporator and condenser), the efficiency of the combined ejector-absorption refrigeration cycle relative to the single effect absorption refrigeration cycle can be increased by more than 30%, but there is not a significant difference in the exergy efficiency of the two cycles.

The main cause of the energy dissipation in buildings in the country, in addition to design style of employment in the town of Bad materials in different parts of the building. It can be simple solutions to the implementation of some of the loss of a significant amount of renewable energy. In this study , optimize energy consumption in an administrative building in Semnan province climate in a bid to replace the window glass - with the designated low dispatch in foreign wall instead of single - walled window with the situation by simulator design builder software was investigated. Results of energy - saving by 12 percent annually in the coolant load, 2 percent in heating load and 11 percent of the total sample building in loads.

The contribution of the building sector to the energy consumption of countries is significant, so in the last few decades, in most industrialized countries, basic measures have been taken to reform the consumption model , using various tools including regulations and criteria . In this study, the use of the type of material used in the walls of the city buildings in the Garmsar city building was analyzed. The comparison of the heat transfer coefficient of each material used on the external walls of the building is modeled and the building is evaluated with basic materials according to the climatic conditions of the city. Finally, using new materials in the outer wall and ceiling, building with double wall is a priority in reducing energy consumption.

Due to the favorable properties of wide regions of the world and has developed a shortage of fresh water in dry areas that already face large-scale development has occurred Such as parts of North Africa and the Middle East, to produce fresh water by desalination to need a lot of energy and a lot of research studies for the development of solar desalination is being done by solar energy With the aim of identifying key technical challenges and potential opportunities for solar energy, A variety of technologies for the optimum amount of solar energy as well as various technologies for solar desalination system includes advanced technique for restoring energy is studied we conclude that the development of solar desalination system for cost-effective and energy-efficient in the near future may be grounds for water supply desert regions of the world. The effects of water cooling with two modes: simple desalination (passive) by installing cooling and desalination of water (active) examined and compared in terms of daily production has been tested. Tests in August (August) in geographical coordinates (N:35°34′,E:53°22′) carried on the basis of the results observed maximum production rate freshwater disabled 0.26 (kg / m2) per hour. Moreover, the daily output disable mode of 1.035 (kg / m2.day) daily 1.530 (kg / m2) reached in active mode.

Healthy and fresh water supply is one of the fundamental issues in different regions of the world, particularly in remote areas is dry. There are several methods for desalination of brackish waters, of which solar distillation devices can be the perfect solution for sparsely populated areas that are of sufficient intensity solar radiation. In this study, we have tried to express the necessity of providing safe drinking water, the fundamentals of performance of solar desalination dealt with the resources available. In the present study the effect of water cooling with two modes: Desalination with heat pipe and manifold (semi-active) and desalination to cooling water and heat Vlvlhhay manifold (active mode) are tested daily production was investigated. Tests in August (September) in geographical coordinates(N:35°34′,E:53°22′)is conducted. Based on the results observed The maximum rate of production of fresh water in active mode 0.43(kg / m2) per hour. As well as the daily yield semi-active mode from 1.87 (kg / m2.day) daily 2.085(kg / m2) reached in active mode.

In this numerical case study, thermal and hydrodynamic behavior of Ferro fluid (water + %2 Fe2O3) in two dimension channel in present of magnetic field has been study by single phase model and finite volume method. Magneto hydrodynamic effect and then impact of adding magnetic Nano and effect of non-uniform magnetic field on fluid has been study. channel’s wall are on constant temperature of 290 kelvin and main fluid inter the channel in 340 K. four magnetic dipole place along channel and the placed the fluid under magnetic field strength of 0.1,0.15,0.2,0.25 .impact of these magnetic field on velocity, pressure, heat transfer rate and Nusselt number studied and it showed very little impact heat transfer enhancement under magnetic field and can be negligible.

Due to the limited fresh water sources and reduce the increasing these resource In recent years a lot of attention to the use of solar desalination for water desalination is available In this paper, a desalination using collector, heat pipe, solar panels and natural ventilation design and built. To increase the efficiency of desalination has used various means Such as pre-heat the water in the collector by heat pipes and water circulation pump and the use of natural ventilation to reduce the pressure of the fluid level To lower the temperature of the water evaporates As well as the use of natural ventilation for cooling water in the steam distillation available on this route After designing and constructing this system, all data were recorded on weather conditions of Semnan And at the end performance of the device in different scenarios were compared.

Study on the type of flow, to design and improve the mechanical systems necessary fluids. May in the new speed measurement tools, such as hot wire flowmeter Hot wire Anemometry, laser dog vane ( Laser Doppler Anemometry ) and the image of the particle image velocimetry poll particles more application of this study was trying to operating theory, applications, benefits and drawbacks. The three methods paid attention to the study conducted HWA method in places where it is appropriate to less heat and lower accuracy is concerned, as well as in places where there is less mobility (due to take pictures of successive) and cost less launch is considered the best method, PIV method is sensitive places and accurate and also of fluids and gases that have a high speed, the best way to assess could LDA that maintain speed.

In this article, indicators of annual energy intensity 13 residential complexes with different characteristics were evaluated and compared. These features include the type of facade, heating and cooling systems, windows, and separate or shared type gas meters are units available in the complex. Introducing selected complexes, specifications hull, heating and cooling systems as well as the energy used in the study and analysis of energy flows in the complex have been discussed. The data processing methodology for calculating the energy consumption rate index have been studied conglomerate. The indices are calculated energy intensity of buildings and structures with different properties in terms of energy intensity compared. Compare energy intensity indicators show that the use of new energy Mtalh like metal siding board (decorative panels) instead facade, windows UPVC windows instead of metal, instead of single-wall and double glass instead of heaters and boilers as well as the use of semi-centralized heating systems or room in the building's energy intensity has considerably decreased. Also, instead of using a separate gas meter gas meter joint, by influencing the behavior of the occupants of the building and create a financial incentive to reduce energy use saves natural gas consumption and decreasing energy intensity building.