Papers by Keyword: Nozzle

Abstract: Additive Manufacturing (AM) [1] is playing every day a bigger role in the automotive industry because of its cost competitiveness, short delivery lead times and potential for design flexibility and optimization. Plastics and polymers are the most common materials used to produce AM parts in this sector, however metal AM is increasing its importance as there are specific applications that require mechanical characteristics that can only be achieved with metals such as stainless steel, titanium, hard steel, copper, aluminum, and others. There is an increasing number of metal AM technologies and Original Equipment Manufacturers (OEMs) competing in the industry with a very widespread list of advantages and disadvantages of each of them. We are at a point where automotive manufacturers need to make a complex decision on which metal AM equipment to purchase. This paper describes the main metal AM technologies and highlight the advantages and disadvantages of each of them. Additionally, three of the most competitive Metal AM technologies are compared: Powder Bed Fusion (PBF), Metal Filament Deposition Modeling (MFDM) and Bound Metal Deposition (BMD) on a specific experimental sample. For this study, a very common and representative automotive part has been chosen that is well suited to be printed in metal and can be manufactured in the three chosen technologies. A nozzle from the automotive body plant used to distribute accuratey a sealant bead onto a body panel before the final assembly operation was selected. These sample parts have been trialed for function and evaluated in general terms from a quality point of view. The conclusions included in this paper will help the automotive industry players understand which technology to use for this specific part and other parts with similar characteristics. Additional work will focus on specific quality characteristics such as material composition, mechanical properties, dimensional accuracy, and specific defects found to compare these technologies in detail. Furthermore, a selection of other automotive parts and technologies will be necessary to enlarge the knowledge on the application of metal AM on this field.

Abstract: A twin-wheel caster with a hole nozzle was developed to cast thin aluminum alloy wire. The lower large wheel had a trapezoid groove with a cross-sectional area of 22.5 mm², and the upper small wheel was flat. Molten-metal flow onto the wheel was controlled by the gap between the wheel and the nozzle, and the ejection angle of the molten metal. When the gap was not appropriate, bulges formed on the free solidified surface of the molten metal on the wheel. The bulges were flattened by setting the gap to the correct size of 3 to 4 mm. The appropriate angle was found to be 60°. A thin wire of 6061 aluminum alloy could be cast continuously at a speed of 5 m/min. The cross-sectional area of the nozzle hole was 3 mm². The cross-sectional area of the as-cast wire was 42.7 mm².

Abstract: The article considers the combined processing methods used in the rocket and space technology products manufacture. The technology of obtaining holes in the nozzles of the liquid rocket engine mixing head is presented. The relevance and necessity of using high-tech technologies in the special equipment parts and assembly units manufacture is justified. The ways of ensuring the process stability and technological parameters increasing are shown, which made it possible to expand the application area of dimensional combined processing using the electrode as a tool. The results obtained allow us to expand the production technological capabilities, as well as to improve the technical special equipment products characteristics in mechanical engineering.

Abstract: When a strip of Al-Si alloy with an Si content of 1% was cast using a vertical-type high-speed twin-roll caster, cracks form in its surface. The effects of the pouring method, the shape and position of the nozzle, and the roll surface texture on surface crack formation were evaluated with a roll caster. The rolls were made of a copper alloy, and the roll speed was 30 m/min. The as-cast strips were bent to investigate the degree of crack formation, and the outer surface of the strips was observed without magnification and with a stereomicroscope to determine the influence of the pouring method, the shape and position of the nozzle, and the roll surface. A roll machined to form V-shaped grooves 0.4 mm deep on the surface of the strips was most useful for reducing surface cracking. Changing the shape of the nozzle tip was second-most effective. There was a clear correlation between the roll surface condition and surface cracking in the Al-Si strip.

Abstract: In this work, the authors tried to solve a typical problem of inexpensive 3D printers using FDM technology: material clogging of the hotend. To cope with the problem, it is necessary to solve the problem of optimization the temperature regimes of the hotend. For this, the temperature fields of the heating device were simulated taking into account the physical properties of the printing materials. Modeling was carried out using the ANSYS software package, the verification of theoretical calculations was carried out in a full-scale experiment. The data obtained was used to upgrade the 3D printer hotend.

Abstract: The article presents the results of experimental studies of differences in the nature of impact destruction of single garnet grains penetrating the target material, and presents the results of numerical simulation (modeling) of the contact interaction of an abrasive particle with a flat obstacle, which allowed determining the volume ablation of the material under the action of a single abrasive particle, and makes it possible to predict the performance of waterjet cutting.

Abstract: Launch and space vehicle structures are required to be extremely weight efficient. The need to achieve the performance required for the engine in the upper stage of a launch vehicle, increase the payload capacity drives rocket engine manufacturers to seek higher thrust level, specific impulse and thrust to weight ratio. The use of high temperature C-C composite materials is an efficient way to reach these objectives by allowing use of high expansion ratio. Nozzle extensions benefiting of the outstanding thermal, mechanical and fatigue resistance of these materials to decrease mass and featuring high temperature margins. A three-directionally reinforced (3D) carbon-carbon (c-c) material nozzle exit cone is selected for the current study. C-C composite exit nozzle must possess excellent stability and strength under extreme conditions for a specified amount of time. Carbon-carbon composites are appropriate materials for applications that require high specific strength at elevated temperatures. The paper describes the thermo structural analysis of a typical c/c nozzle exit cone.

Abstract: Article is devoted to a research of aerosol systems of supply ventilation. Expediency of creation and use of water and aerosol systems for decrease in concentration of fine-dispersion dust in working zones, and as a result, decrease in negative impact on operators of various productions is proved. The design of a centrifugal mechanical one-slot-hole nozzle is proposed. Problems of dust content in air of a working zone and impact of particles of PM10 and PM2,5 on an organism of workers are considered.

Abstract: The paper presents the experimental results that allow determining optimum quenching conditions for solid rocket motors (SRM) at the stage of firing bench tests (FBT) in gas dynamic tunnels (GDT) with altitude simulation. The work describes main design approaches for quenching unit enabling reduced thermal insulation (TI) destruction by 15-20% after finish of SRM operation due to aftereffect decrease, as well as reduced values of scattering of TI undamaged layer thickness up to 10% owing to uniform cooling.If necessary, drying accompanied with emissions of TI gaseous products and remnants of k-phase fuel components is run in GDT, which allows improving environmental safety of working facilities and shortening the time for evaluation of SRM design parameters.

Abstract: In this paper, the Cumulative Usage Factor (CUF) of a High Pressure Core Cooling System (HPCS) reactor nozzle of a Boiling Water Reactor was calculated. This fatigue damage has been caused by the sudden injection of cold water into the reactor vessel through such nozzle. For this purpose, a three-dimensional analysis was carried out. Accordingly, a transient heat transfer analysis was developed. The temperature distribution was determined. With this information, the stress analysis was carried out. The safe end was restricted to move along its axial direction and the forging end was free to expand axially and radially. The resultant stress field established the magnitude of the alternative stresses. In the last step, a fatigue analysis was developed. The most critical point is the junction of the nozzle with the thermal sleeve. The fatigue performance was evaluated during a period of sixty years. It was assumed that 1.5 cycles per year will take place. The fatigue curves of ASME code section III were used. The results showed that the Cumulative Usage Factor (CUF) vary with the temperature injection, being 0.4090 when the water injected was 4.44°C and 0.3797 when the water temperature was 37.77°C. Both of them were estimated for a period of 60 years of operation. Therefore, damage is reduced as the temperature of the injected water increases. Besides, it is advisable to at least follow the recommendations of the NUREG ́s 1800 and 1801 [1, 2]. In this way, the aging of the nozzle is adequately managed.