• MACHINES

    On pressure drop and airflow directivity ability of air vents on automobile cabinets

    Machines. Technologies. Materials., Vol. 16 (2022), Issue 3, pg(s) 90-92

    In this study, airflow directivity ability and pressure drop values of air vents where placed on the front console of automobile cabinet were investigated with computational fluid dynamics analysis. One of the aims of these studies is the airflow performance impact of design changes on air vents. Therefore, parametric studies were conducted with diffuser structures having 3, 4, 5 blades and 16mm, 20mm, 24mm blade width and 3mm, 4mm blade thickness. These variations were created to determine the effects of the number of blades, blade width and blade thickness on air flow and pressure drop performances of automobile diffusers. The impact of automobile diffusers on thermal comfort inside of the cabinet has been detected—correlations which give pressure drop and airflow angle were obtained according to analysis results. Thus, equations giving airflow direction angle and pressure drop within specific parameters were obtained without computational fluid dynamics analysis. In this way, a faster approach was provided to reach related performance values on automobile diffuser design.

  • Simulation of nanocrater formation during laser-induced phase transitions

    Materials Science. Non-Equilibrium Phase Transformations., Vol. 5 (2019), Issue 4, pg(s) 138-141

    A theoretical study of the process destruction of a solid surface under the action of a powerful radiation impulse is carried out. The peculiarities of the dynamics the surface destruction of the material and the features of the space-time dynamics of the gaseous phase were studied. This phase occurs as a result of local phase changes on the surface of the irradiated material. The differential equation to describe the dynamics of the corrosion crater formation on a solid surface was researched. This equation is analyzed together with equation of near-surface pressure dynamics. The asymptotic analysis for crater equation gives the basis to assert that mathematical interpretation of process of destruction corresponds to actual temporal dynamics of formation of a crater on the substance. The numerical simulation of the formation of a nanocrater with a model form of an active laser impulse is given. The test calculations correspond to experimental observation and theoretical ideas about the process of development of a corrosion crater under laser pulsed irradiation.

  • The problem of control of the viscous incompressible liquid motion through a pipeline system

    Mathematical Modeling, Vol. 3 (2019), Issue 1, pg(s) 10-19

    In this paper the solution to the inverse problem of hydrodynamics of the viscous incompressible liquid, moving through pipes of the circular cross-section without a free surface, is given. For a given mass flow at one of the outlets of the pipeline system, the required pressure at its inlet is determined. The numerical simulation of the change in liquid velocity in the pipeline system is carried out for the given pressure variation at the inlet of the system.

  • MACHINES

    EMBEDDED RESEARCHES ON ADAPTIVE PARAMETRIC MODELING OF HYDRAULIC GEAR PUMPS

    Machines. Technologies. Materials., Vol. 12 (2018), Issue 3, pg(s) 90-93

    This paper presents some of the research results on a fundamental and applicative procedures regarding the integrated intelligent conception of a Romanian series of hydraulic gear pumps. Following the analysis of the pump series in the manufacturing process, the requirement for a modernized parametric design of this product has been identified. Thus, we observed the beneficiaries’ requirement for certain flows that are currently not provided by the current range of pumps. The parametric design of the pump leads to an easy and adaptive modification of the supplied flows, resulting in an innovative methodology which is very useful for the design and process engineers. The methodology is based on a computer-aided 3D modeling, specific pressure, drive torque, flow rate, etc. Each of these parameters leads to the intelligent modification of the certain geometric and functional features of the pump series designed to be adaptable to the dynamic demands of a modern economy.

  • MACHINES

    THE INFLUENCE OF LUBRICATION OILS AND FILTERS ON THE OILS PRESSURE, TEMPERATURES AND FLOW DURING ENGINE WARM-UP AT SUMMER CONDITION

    Machines. Technologies. Materials., Vol. 10 (2016), Issue 10, pg(s) 13-16

    The key issue to an automotive engine’s reliability and its durability is the quality of the lubrication system. The primary task of the lubrication system is to provide a continuous supply of filtered oil between two sliding surfaces. By using adequate lubrication oils will reducing friction between moving mechanical parts. Rheological characteristics of lubricating oil directly caused the friction losses due to internal engines mechanisms (piston group, valve train, fuel pump, crankshaft, bearings and seals, etc.). The main components of lubrication system has a poor lubrication during cold start up process of an IC diesel engine and thus is necessary a proper lubricating oil to full fit the complex demands of all engine components and subassemblies. The aim of this paper is experimental investigating of the influence for different classes lubricating oils characteristics and oil filters which are present in market of Republic of Kosovo, especially those with lower prices on engine oil pressure, temperature and flow during start up until the oil warms up some. The obtained results are taken from measuring device which is installed into Fiat passenger car with Spark Ignition Engine for different working regimes.

  • ELASTIC PHASE TRANSITION IN METALS: THE PRESSURE EFFECT

    Materials Science. Non-Equilibrium Phase Transformations., Vol. 3 (2017), Issue 3, pg(s) 104-107

    At high pressures (the pressure is comparable with the bulk modulus) the crystalline lattice may become unstable relative to the uniform shear deformations, and as a result the low symmetric crystalline structures will appear (the so called “elastic phase transitions”). The order parameters at these transitions are the components of the finite deformations tensor. The stability of the high-pressure phases is defined by the nonlinear elasticity of the lattice (the third, fourth etc. order elastic constants). Here the different cases of stability loss at hydrostatic pressure of the cubic and hexagonal structures are considered. The relation between the second, third and fourth order elastic constants is given, which defines the possibility of the first order deformation phase transition. The jump of the order parameter and the height of the potential barrier are defined by the third and fourth order elastic constants. As an example, the experimentally observed elastic phase transition in vanadium at P≈ 69 GPa from bcc to the rhombohedral phase is analyzed, and the possible structural transitions in bcc Mo and W at P≥700 GPa are considered. The stability of the Ru in the pressure interval 0÷600 GPa is also analyzed. The necessary values of the different order elastic constants for Mo, W and Ru are calculated in the framework of the density functional theory using VASP (Vienna Ab initio Simulation Package).