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The purpose of this paper is to provide an analytical method of jet flow injection direction and to determine the influence of oil nozzle structure parameters on oil injection direction, thus providing the design method of oil nozzle structure parameters.

A model of oil injection loss is established to analyze the influence of oil nozzle structure parameters on oil injection direction. The computational fluid dynamics method is used to simulate the process of the deviation of jet flow injection direction. The deviation of jet flow injection direction with different oil nozzle structure parameters is calculated and their variations are obtained. Moreover, the deviation of jet flow injection direction with different oil nozzle structure parameters is tested to verify the analysis results.

Results indicate that radial velocity caused the deflection of the oil injection direction. The deviation of jet flow increased as the nozzle slenderness ratio decreased. The design method of the nozzle slenderness ratio (greater than five) is proposed to avoid the deviation of injection direction, and it is necessary to consider the matching between the nozzle slenderness ratio and pipeline pressure. The computational results coincide well with the experimental results.

The research presented here analyzed the influence of oil nozzle structure parameters on oil injection direction via a numerical analysis method. It also leads to a design reference guideline that could be used in jet lubrication, thus controlling the direction of the injection jet accurately.

AS has often been iterated, the Harrier is a close support fighter with the facility for extremely short, or even zero, ground take‐off runs. This facility is achieved by directing the jet efflux of the Rolls‐Royce (Bristol Engine Division) Pegasus engine out of four rotating nozzles moving in symmetry, these rotating nozzles vectoring the engine thrust over 98½ deg. of movement from aft to forward of the vertical. The nozzles are rotated by shafting and chains, powered by an air motor, and controlled by a single lever in the cockpit. The complete system is termed the Engine Nozzle Actuation System, and pilot selection and air motor output comprise the input and error signals of a simple servo loop controlling engine nozzle position (Fig. 1).

Air is sucked from the boundary layer at the rear of an aircraft surface through apertures connected to an air compressor delivering to a jet propulsion expansion nozzle and may comprise the whole of the airflow through the nozzle or alternatively air from in front of the aircraft may also be passed through the compressor, or through some stages only of a multi‐stage compressor. All or part of the air may be heated by fuel injected through combustion nozzles, and the compressor may be driven by a gas turbine on the same shaft or by a reciprocating engine. The combustion air may be preheated by a heat‐exchanger in the exhaust. The jet nozzle may be the sole propulsive means or an airscrew may be mounted forwardly on the compressor shaft. Slots for intake of boundary layer air may be provided at the points at which the boundary layer tends to break away and may be formed as divergent channels or may comprise merely a scries of holes in the aircraft surface. A scries of such slots may be provided with means by which selected slots only are in operation at any given time, and a pitot tube projecting into the boundary layer in front of a slot may be employed to indicate the condition of the boundary layer before that slot. In landing air may be ejected through supplementary nozzles directed forwardly and downwardly to provide aerodynamic braking. The air may be passed for cooling a radiator mounted in the wing or fuselage. Air taken in forwardly of the aircraft may be compressed by a compressor in the fuselage and then distributed, after heating by fuel injection nozzles, to jet tubes in nacelles in the wing through which also passes the boundary layer air As shown in FIG. 9, air extracted at the trailing edges of the wing of an aircraft passes forwardly through a nacelle and through the first stage CI of a compressor. Part then flows directly to a propulsion nozzle at the rear of the nacelle while part passes through a further stage C2 to a combustion chamber fitted with combustion nozzles ch and through a gas turbine T and heat exchanger E, which heats air bypassing the combustion chamber and turbine, to the propulsion nozzle. The turbine T drives the compressor CI, C2 and an airscrew. In FIG. 11, air is passed from slots 1 in the wings through ducts 2 to a central compressor 4 and thence to a reaction nozzle 6. The compressor 4 is driven by a reciprocating motor 5 which also drives an airscrew 3. In FIG. 12, air from slots 7 in the wings passes through compressors 8 in nacelles in the wings and thence to a reaction nozzle 14. The compressor 8 is driven by a turbine 9 supplied through ducts 12 with air admitted centrally at the nose of the aircraft, compressed by a compressor 10, driven by a reciprocating motor 11, and heated by fuel injection nozzles 13. The exhaust from the turbine 9 is to the jet 14. In FIG. 13, air entering a wing 15 through slots 16, 17 passes through the wing spar 18. to the first stage 19 of a compressor in a nacelle beneath the wing. Part then flows by an annular passage 19a to a propulsion nozzle 20. Part passes through a second stage 21 of the compressor to a combustion chamber 22 fitted with combustion nozzles and through a gas turbine 23 to the propulsion nozzle 20. The turbine 23 drives a propeller 24. Specification 512,064 is referred to.

This study aims to improve the survivability and maneuverability of the fighter,and study the stealth performance of fighter in the jet noise of aeroengine, it is of great significance to study the jet noise characteristics of double S-bend nozzles.

The multiparameter coupling and super-ellipse design methods are used to design the cross section of double S-bend nozzle. Taking unsteady flow information as the equivalent sound source, the noise signal at the far-field monitoring points were calculated with Ffowcs Williams–Hawkings (FW–H) method, and then, the sound source characteristics of the double S-bend nozzle are analyzed.

The results show that the internal flow of the S-bend nozzle with rectangular section is smoothed and the aerodynamic performance is better than super-ellipse section, the shear layer length of rectangular section is longer, the thickness is smaller and the mixing ability is stronger. The sound pressure level of the two S-bend nozzles decreases with the increase of the monitoring angle, and the sound pressure on the horizontal plane is greater than the vertical plane. In the direction of 40°–120°, the jet noise of rectangular nozzle is smaller, and the multiparameter coupled rectangular cross section structure is more applicable.

It is beneficial to reduce the jet noise of the engine tail nozzle and improve the stealth performance of the aircraft.

There is very little research on the jet noise characteristics of the double S-bend nozzle. The multiparameter coupling and the super-ellipse method are used to design the nozzle flow section to study the aerodynamic performance and jet noise characteristics of the double S-bend nozzle and to improve the acoustic stealth characteristics of the aircraft.

The purpose of this paper is to demonstrate the use of selective laser melting for producing single and double chamber laser cutting nozzles. The main aim is to assess a whole production chain composed of an additive manufacturing (AM) and consecutive finishing processes together. Beyond the metrological and flow-related characterization of the produced nozzles, functional analysis on the use of the produced nozzles are carried out through laser cutting experiments.

SLM experiments were carried out to determine the correct compensation factor to achieve a desired nozzle diameter on steel with known processibility by SLM and using standard nozzle geometries for comparative purposes. The produced nozzles are finished through electrochemical machining (ECM) and abrasive flow machining (AFM). The performance of nozzles produced via additive manufacturing (AM) are compared to conventional ones on an industrial laser cutting system through cutting experiments with a 6 kW fibre laser. The produced nozzles are characterized in terms of pressure drop and flow dynamics through Schlieren imaging.

The manufacturing chain was regulated to achieve 1 mm diameter nozzles after consecutive post processing. The average surface roughness could be lowered by approximately 80 per cent. The SLM produced single chamber nozzles would perform similarly to conventional nozzles during the laser cutting of 1 mm mild steel with nitrogen. The double chamber nozzles could provide complete cuts with oxygen on 5 mm-thick mild steel only after post-processing. Post-processing operations proved to decrease the pressure drop of the nozzles. Schlieren images showed jet constriction at the nozzle outlet on the as-built nozzles.

In this work, the use of an additive manufacturing process is assessed together with suitable finishing and functional analysis of the related application to provide a complete production and evaluation chain. The results show how the finishing processes should be allocated in an AM-based production chain in a broader vision. In particular, the results confirm the functionality for designing more complex nozzle geometries for laser cutting, exploiting the flexibility of SLM process.

The purpose of this study is to analyse the problem of high binder content in sand mould and to solve it. Meanwhile, to increase build speed, especially for heavy casting’s sand mould with a high value in layer height, such as 2 mm in construction instead of the industry standard of 0.3 mm, line forming for three-dimensional (3D) sand mould printing is researched.

Brief introduction of 3D sand mould printing and key issues are given first. Then, this paper quantitatively analyses binder content in sand mould. Finally, to acquire sand mould with appropriate binder content and high build speed, line forming combining traditional furan no-bake sand manufacture technique is researched, as well as relevant feasible schemes and current progress.

The study shows that compared with traditional technique, binder content in sand mould produced by available 3D printing technique is too high, bad for sand mould’s properties and quality of castings, while line forming brings guaranteed binder content and improved build speed.

More experiments are needed to demonstrate quantitative analysis of binder content and to obtain flowability of moist sand, detailed structure design of nozzle and practical build speed, as well as methods of circulation of materials considering solidification time.

Line forming with higher build speed and suitable binder content means excellent properties of sand mould and castings as well, bringing obvious implication for moulds industries and manufacturing industry.

This new method could increase build speed and meanwhile guarantee binder content. Thus, its application prospect is promising.

To facilitate future development of the cooled gas‐turbine, more test information is needed on the effectiveness of cooling in an actual turbine operating at high gas‐temperatures. Part I of this paper deals with some design aspects of a single‐stage experimental turbine built to enable an experimental investigation to be carried out on the air cooling of nozzles and blades. The turbine, built for operation at high gas‐temperatures, was fitted with internally air‐cooled blades having a large number of small cooling passages running the whole length of the blades. A description is given of the pressed powder technique used to introduce the small passages in blocks of heat‐resisting material from which the blades could be machined. Mention is made of some of the difficulties encountered in this method of manufacture and also of the need for careful consideration of suitable methods of disposal of the cooling air when internally cooled nozzles and blades of this form are used.

The extrusion-based additive manufacturing method followed by debinding and sintering steps can produce metal parts efficiently at a relatively low cost and material wastage. In this study, 316L stainless-steel metal filled filaments were used to print metal parts using the extrusion-based fused filament fabrication (FFF) approach. The purpose of this study is to assess the effects of common FFF printing parameters on the geometric and mechanical performance of FFF manufactured 316L stainless-steel components.

The microstructural characteristics of the metal filled filament, three-dimensional (3D) printed green parts and final sintered parts were analysed. In addition, the dimensional accuracy of the green parts was evaluated, as well as the hardness, tensile properties, relative density, part shrinkage and the porosity of the sintered samples. Moreover, surface quality in terms of surface roughness after sintering was assessed. Predictive models based on artificial neural networks (ANNs) were used for characterizing dimensional accuracy, shrinkage, surface roughness and density. Additionally, the response surface method based on ANNs was applied to represent the behaviour of these parameters and to identify the optimum 3D printing conditions.

The effects of the FFF process parameters such as build orientation and nozzle diameter were significant. The pore distribution was strongly linked to the build orientation and printing strategy. Furthermore, porosity decreased with increased nozzle diameter, which increased mechanical performance. In contrast, lower nozzle diameters achieved lower roughness values and average deviations. Thus, it should be noted that the modification of process parameters to achieve greater geometrical accuracy weakened mechanical performance.

Near-dense 316L austenitic stainless-steel components using FFF technology were successfully manufactured. This study provides print guidelines and further information regarding the impact of FFF process parameters on the mechanical, microstructural and geometric performance of 3D printed 316L components.

THE problem of the expansion of a compressible fluid with friction and heat flow is one of great complexity. In this treatment it has been simplified to a one‐dimensional problem and the resulting relationships are thermodynamic. An expansion of this type cannot be described as reversible due to the presence of friction, and from this aspect the analysis may be suspect. However, any practical process is irreversible and it is common practice to apply to such processes an analysis which is theoretically confined to changes which occur reversibly. Thus, although the degree of irreversibility may be greater than usual in this case, there are many precedents for allowing the use of reversible thermodynamics in the analysis of irreversible changes. The relations for the expansion are well known, but the writer believes the analysis and discussion on the choking conditions of a nozzle are more general than anything yet published.

This paper aimed to propose a novel fused-coating-based additive manufacturing (FCAM); the study of key process parameters and mechanical tests are performed to determine the proper parameters when building metal components.

Sn63Pb37 alloy is deposited in an induction heating furnace with a fused-coating nozzle to build metal parts on a copper-clad substrate. The process parameters including nozzle pressure, nozzle and substrate temperature and nozzle gap between substrate are analyzed and found to have great influence on parts quality. The mechanical property tests between the fused-coating and casting parts are performed in horizontal and vertical directions. Also, the optical microscopy images are used to ascertain under which conditions good bonding can be achieved.

A FCAM method is proposed, and the exploration study about the manufacturing process is carried out. The critical parameters are analyzed, and microscopy images prove the suitable temperature range that requires to fabricate metal parts. The mechanical tests confirm that tensile strength of printing parts is improved by 20.4 and 11.9 per cent in horizontal and vertical direction than casting parts. The experimental results indicate that there is a close relationship between process parameters and mechanical properties.

This paper proves that FCAM provides an alternative way to quickly make functional metal parts with good quality and flexibility compared with other additive manufacturing methods. Moreover, good mechanical property is achieved than conventional casting parts.