مجله مهندسی مکانیک شریف
سال بیست و ششم شماره 1 (بهار و تابستان 1389)

In the present study a new method for thermal environment, human life is used. The purpose of this research method to determine the inverse temperature and the walls of a room air temperature conditions in order Yknfrh Residential Thermal comfort. With this method, which is a system of equations describing Bdvz, "Reverse modeling" call. In this system of equations for Khvshvz listed by method "Mnzmsazy Tykhvnvf" is used. Inverse method to determine optimum conditions leading to thermal) temperature of the walls and air temperature (around the person and situation, with the constraints set error and uniformity, temperature and flux on the body, the person required to stay within the desired temperature is. Results indicate that answers obtained from the inverse method, in addition to thermal comfort conditions throughout the establishment of residential space, such as dissatisfaction with the problems caused by the radiation phenomenon are also asymmetrical.

One of the main objectives in the wind tunnel, creating a manageable and reliable flow with minimal disturbance) is the turbulence in the business section. Factors increasing severity of disturbance in the flow separation point and Napaydaryha work at the beginning and end of the tunnel is Mnqbzknndhy. Among the various methods of reducing the intensity level work in turmoil, forced transport stream using a thin wire installed in the output Mnqbzknndh, one of the newest and is Kmhzynhtryn methods. In this study the effect of thin wires installed at four positions in the Mnqbzknndh convex, the flow pressure distribution is investigated. Results show that the flow behavior in low and high speeds for Mnqbzknndh different. By installing a thin wire in the $ frac {x} {L} = 0.79 $, 54 cm from the starting point work, adverse pressure gradient than the other positions, and thus weaker than the flow is unstable. For this, the lowest intensity of turbulence in the wind tunnel working section has been made.

In this study, using thermal operations at different temperatures and different speeds Srdkrdn on the steel 340AISI, structures of the ferrite grain size was different. Next, the operation between the critical heat Tabkary operation at different temperatures and thermal annealing austenitic) austempering (ferrite phase structures Bynayt reached. Ferrite grain size number standard 112ASTM-E, and the percentage of its volume using image analysis to determine was. Tabkary course between the critical temperature thermal operations were selected so that the volume percent ferrite phase almost identical in all structures) about 34% (is. Test results of mechanical properties such as hardness, elasticity, and shock showed that like other materials, with Ryzshdn ferrite grain size, hardness and strength ncreases. between grain size and yield strength of the relationship is established Hull patch. Ryzshdn seeds also reduce the uniform elongation and total elongation increases.

Zanvyyha Saz·hyy behavior as part of a curved pipe under bending loadings paginal Drvnsfhhyy and drive) without internal pressure associated with it (has been investigated. Coefficients flexibility and features as the focus of tension members, raised under the loadings were examined and their changes geometric parameters and loading conditions using finite element method evaluation, and results were presented form chart. It also reviews the results of the present results that approximate the relationship guidelines in coming compared to other sources, and compliance issues or disputes is shown.

Despite lack of attention to solving the boundary between materials in the field, even using high precision merical solution methods, such as Tkhyy S·hmygvn method (PPM), to disorders such as instability and divergence over the results of the numerical solution of the process or lead to incorrect results. In order to prevent such cases, the methods used Dnbalsazy border. In Dnbalsazy border procedures, position and shape of the boundary etween two materials in each set timeframe, then properties, including the border cells) mixed cells (using a special relationship as "mixed model" is calculated. In the present study for the numerical solution of equations Gvdvnfy PPM method used and to increase the accuracy of this method in dealing with issues Chndmadhyy, the types of procedures Dnbalsazy boundaries, fluid volume method (VOF) is selected. Among the existing models of mixed model "Hmfshar Hmanrzhy and models "volume fraction fixed" order and selected by appropriate model, the results of the two is compared. Numerical results obtained from the VOF method in solving Chndmadhyy shock tube, Mlahzhyy improvement compared with PPM method shows.

Primary material used in the preparation of magnetic nanoparticles has Bhszayy important. Among the material factor affecting Kmplksknndh of material particle size, temperature Zyntrkrdn and magnetic properties of barium ferrite powder hex Thyhshdh sol-gel method is combustion. In this article the importance of considering the type and amount Kmplksknndh factor in influencing the magnetic properties of particles Thyhshdh sol-gel combustion method, two factors Kmplksknndh citric acid and glycine in the preparation of powdered barium ferrite nanoparticles hex used, then using vibrating Mghnatyssnj (VSM), Scanning Electron Microscope (SEM) and X-ray diffraction (XRD) impact on the operating magnetic properties, structural and fuzzy Hgzafryt barium powder was investigated. The best hard magnetic properties at a temperature of 900 ° C and 31 nm particle size given by glycine Kmplksknndhy agent is obtained.

The purpose of this document delivery method to obtain the optimal initial sheet is Pressing parts. In this point of view how the pieces of ductile rupture and shrinkage is predictable using this method in the design stage is very convenient format. In other words, having the dimensional pieces, profile sheets and the mechanical process of hysical conditions can achieve all these goals. In this way the overall deformation theory Khmyrsany (plasticity) is used. According to the basic sheet on page Qrardashtn horizon, the elevation change at any point is unclear and the issue of two-dimensional case is reduced to three dimensions in the reduced volume of calculations is highly effective. In order to access the most appropriate initial guess in solving systems of equations, a special method Tsvyrkrdn elements in the piece on page three dimensions on the horizon is used. In addition to solving the equations system card optimal initial Krnshhay the main component is determined. The results of this technique for several industrial piece with experimental results and also compare the available commercial software is located.

In this study the behavior of a nozzle Dvsyalhy induction has been investigated. This nozzle design approach based on analysis of single phase flow conditions in connection with the performance of a nozzle base is used a method to estimate the size of the liquid duct diameter based on Bernoulli's equation based on the occurrence of bottlenecks choking puts forward. Revealed using an experimental array with the ability to provide simultaneous and reliable flow of compressed air, fluid flow and electrical voltage is tested. Pressure compressed air through the dielectric insulating layer on the electrode strengthen induction and exacerbation due to voltage electric field are enhanced Bardarsazy. Rising at a constant voltage suggests there is an optimum pressure of the passing of ressure contact with the strengthening Bardarsazy Induction Bardarsazy is weakened. Dubai increasing henomenon Khysshdgy liquid electrode decreased induction Bardarsazy Is; delay in the occurrence of this phenomenon requires higher levels of applied air pressure is. Low performance compared to the base of the match revealed a very good quality and quantity has confirmed that the usability of the approach is a single phase. Revealed in addition to providing higher levels of induction in Bardarsazy pressure and high voltage, low consumption of compressed air also similar in all conditions to Nozzles show puts base.

Mrtbhyy steels with different thicknesses of the layout and simple carbon steels and austenitic Zngnzn as the electrode melting process electric Srbarhyy, were produced. Charpy impact energy of steel samples in a state Mrtbhyy Tqsymknndhy left was evaluated. The results suggest that the type specimens Zrbhyy energy and volume fraction of phases Tshkyldhndh depends. Log in using and distributing hard Tnshkrnsh area under the curve diagram obtained from tensile testing Tkfaz·hay Tshkyldhndhy composites, two mathematical models in order to predict impact energy law via mixed phase samples are presented. Between practical results and the results of two models offered, the agreement is well established.

Nowadays License Nymhmghrvq) SPP ((SPP)} for Extremist vessels, according to the high efficiency and having a growing has increased maneuverability. With regard to the performance of this type of Butterflies in phase mode) climate (and The rate High rotational work and numerical analysis of the calculation is very complicated. Tests conducted on the geometry and physical conditions permit it shows that geometric parameters such as number Prhha step, form the working conditions and blade profiles such as immersion height, angle, speed and rotational speed floating license Bhszayy impact on hydrodynamic performance license is Nymhmghrvq. In this article, using data from the experimental results reference {1-5} to determine the action of transient conditions, and with the help of boundary element method to the hydrodynamic calculations and analysis of this type of license has been paid. The experimental results as major boundary conditions in solving boundary element method is applied. In the present method Nymhmghrvq The first two types of license) 101SPP (and the second type of license Nymhmghrvq) 102SPP (intended for the calculation is also included results coefficients Trust, torque And efficiency compared with other experimental results show that boundary element method with boundary conditions defined and can be desirable and satisfactory for this type of analysis is an appropriate reference Butterflies.

Ayrlyft pump device that is created by using levitation force accumulation of gas injected in a liquid column, capable of pumping liquid or solid particles desired in the liquid height is higher. In this article the effect of parameters such as effective diameter, float ratio, tube length and flow regime on the performance of a pump Ayrlyft, the form has been studied numerically. Also in the study area conditions and optimize the performance of pumps have been established. Comparing the results of numerical analysis with experimental results indicates the accuracy of this method is desirable. Results indicate that increased buoyancy and reduced diameter ratio improved performance is the pumps. It also increases the effect of pipe length on the performance of these pumps Bhszayy not.

Explosive welding process, two or more plates) page or the base metal and metal whisk page (in a lot of pressure created by the Madhyy explosives, are connected to each other. The article also introduces Farsybr connection and related calculations, and Given relations explosive welding is done in aluminum and copper metals. Trahyshdhy onding strength tests created with shear will review. Finally, the results of cutting experiments and the ratio of velocity to minimize the amount of treated areas not connect, relationship to explosive loading by applying the appropriate correction factor, and the new model is provided. Farsybr result that the connection used in addition to features aligned connection Ghyrhmjns metals, can be used in explosive welding process evaluation of the important relationships as well. to access and control factors that effect the other explosive compounds bind metal Farsybr connection can be better controlled and factors involved in the process to achieve a successful connection completely. This way of exorbitant costs and time spent on preventing long experiments.

Byshghlty one of the most dangerous types of accident scenarios is. The purpose of this study how much impact on the stability of the suspension parameters Rolling car sports car sports UV S. (in terms of incidence Byshghlty. For this purpose, the equations of state vehicles Byshghlty Shbhaystayy plus rigid and suspension, dynamic stability index was determined. Then the full model with 105 degrees of freedom in the ADAMS environment using ehicle as a reference 320ML vehicle information, has been developed. to ensure the development of model behavior given the virtual environment, tried to through the simulation, the behavior of the virtual model tandard aneuvers with the actual vehicle test results reference is Shhgzary. Then change the parameters of the suspension hhgzary model with acceptable dynamic behavior, and how much of the critical parameters in the incidence over two maneuver Ghlty Zmayshl Qlabmahy and is presented. In the end, in order to study the behavior Byshghlty about static stability And vehicle dynamics via check up the results, process design and development vehicle with minimal cost and time, in order to achieve safer car Byshghlty exposure conditions change.