نشریه فناوری در مهندسی هوافضا
پیاپی 2 (پاییز 1396)

Smoothed particle hydrodynamics (SPH) is a relatively new particle and meshfree numerical method which is highly noticed during the last few decades. In comparison to conventional grid-based computational fluid dynamics (CFD) methods, smoothed particle hydrodynamics (SPH) has some unique advantages when it comes to modeling multiphase flows and complex physics. Smoothed particle hydrodynamics (SPH) is a promising computitional fluid drodynamics (CFD) method but it is still in progress. This study deals with the evolution procedure of SPH, its pros and cons, using steps and its applications specialy in aerospace field. In the final section of this paper, we have tried to classify all industrial and research applications of the Smooth Particle Hydrodynamic (SPH) method. Among these applications, progress in the field of aerospace engineering will be studied more widely. At the end, conclusions will be made on the submitted content. At the end, conclusions will be made on the submitted content.

The purpose in this paper is to express a suitable process of modeling and simulation of a ballistic launch vehicle and introducing necessary mathematical solutions for the process. This vehicle is a three – stage ballistic launch vehicle such that each stage has independent condition and characteristic such as mass characteristic, aerodynamic characteristic, propulsion characteristic and control characteristic. The suitable coordinate systems are introduced and analyzed for modeling, such as inertial coordinate system, earth coordinate system, navigation coordinate system and body coordinate system. The equation of motion of this ballistic launch vehicle with respect to earth frame and navigation frame are considered and transformation matrices are mentioned to express definition of vectors in coordinate systems. In this procedure the earth is modeled as an ellipsoid surface with a gravitational field model according to World Geodetic System 1984. Avoiding singularity, quaternions are considered as rotational states instead of Euler angles. Finally, the results of simulation are presented and analyzed graphically.

Exposure of animals and humans to space flight conditions has resulted in numerous alterations in their physiological parameters. As a cell is the functional basic unit of living organisms, to better understand the changes at the function level, it is necessary to comprehend the changes at cellular and tissue levels. Although experiments in real microgravity in space are rare and expensive, similar experiments can be conducted on the ground. A clinostat is a device which uses rotation to negate the effects of gravitational pull on the growth and development of living organisms. It has been used to study the effects of microgravity on cell cultures and embryos in animal and plants. There are some types of clinostat: single axis clinostat and two axis clinostat (Random Positioning Machine). A random positioning machine (RPM) rotates biological samples along two independent axes to change their orientation in space in complex ways so as to eliminate the effect of gravity. Both of these devices are used to simulate weightlessness on cell cultures.

In liquid rocket engine design, because of the combustion due to the high temperatures and high rates of heat transfer (1MW / m2 to about 160MW / m2 ) of hot gases to the chamber walls, the cooling thrust chamber is of utmost importance. Also, the thrust chamber cooling design, the selection of appropriate methods, as well as the design and topics related to thrust chamber cooling ducts, double glazing and thermal coating are very important. Liquid propellant engine in the wall of the combustion chamber and nozzle is a necessary part in order to prevent the failure of a cooling system using engine block resistance. In this paper, the combustion process is investigated using a computational fluid dynamics method. To do this, first the similar works in the field are reviewed and then the equations that exist for this process are extracted to determine what equations need to be solved. By examining this method, it was determined that the chosen numerical method could be used to solve the combustion equation. Finally, the simulation results for the geometry in different fluxes are studied which led to acceptable outcomes

The cultivation of higher plants plays an essential role in bio-regenerative life support systems for food production, CO2reduction, O2 production, as well as for waste recycling and water management. Fresh crops are also expected to have a positive impact on the crew psychological health. Space has unique conditions for biological studies.Biological samples in the space are subject to various stresses including zero gravity, microgravity, irradiation, vibrations, magnetic fields and microorganisms. The effect of space stresses that living organisms are important for human long-duration missions to space and for the improvement of science and technology. Sending plant biological samples to the space needs the design and construction of plant growth systems. At first, these systems had a simple structure, and then they becamemore advanced during the flight. The study of these systems is important in terms of theirappearance, lighting system, food circulation, ventilation system and temperature. In this paper, plant cultivation systems are studied in Salyut Space Station,Mir, Space Shuttle and International Space Station.

Due to the problems in the country (Islamic Republic of Iran) for purchasing aircraft and aircraft old fleet, a solution should be proposedfor this problem. One way to address this need is designing and manufacturing the aircraft in the country.According to the previous investigations carried out, 180-seater passenger planes with a range about 5,000 Km are part of the requirements of the country. In this paper, the costs of design, construction and operation of this type of aircraft has been studied. Also, the inventory costs in the United States of America have been investigated and compared with the costs in the Islamic Republic of Iran. There are three main objectives in this research: the first is to estimate the total expenditures in terms of the different phases of the design, construction and operation; the second concerns reducing design costs to much less than the costs of construction and mining; and finally, the third involves an analogy of the costs of design and production in Iran versus the U.S.