Discharge Hole Research Articles

Microstructure Characterizations of Electrodeposited Magnesium after Discharge/Charge Cycles for Rechargeable Magnesium Battery

Rechargeable magnesium (Mg) batteries attract lots of attention owing to their high theoretical volumetric energy density and low cost from the natural abundance of Mg. Additionally, Mg is less prone to dendrite growth during charging, improving the battery safety. While most studies of rechargeable Mg batteries focus on developing new electrolytes and their performances, the microstructure of the Mg metal anodes during discharge/charge cycles is not fully characterized. Therefore, in this report, we investigated the microstructure evolution of electrodeposited Mg after discharge/charge cycles on both a bulk Mg metal anode and a copper (Cu) current collector in an all phenyl complex (APC) electrolyte.The electrodeposited Mg on both the Mg anode and the Cu current collector at a current density of 2.25 mA/cm2 with a capacity of 1.5 mAh/cm2 show uniform distributions of Mg grains with an average grain size of about 1 to 2 μm. Subsequent Mg stripping with intermediate current density (0.75 mA/cm2) results in non-uniform discharge holes and possible local exposure of the substrate underneath, which could deteriorate the anode integrity. In contrast, the stripped electrodeposited Mg at relatively large (2.25 mA/cm2) and small (0.25 mA/cm2) discharge current densities show dense and uniform discharged holes on the surface. The microstructure evolution of the electrodeposited Mg on different substrates will be discussed based on the plating/stripping overpotentials and the interfacial impedances of the electrodeposited Mg under different conditions.

Microstructure Evolution of Electrodeposited Magnesium on Copper Current Collector during Cycles for Anode-Free Rechargeable Magnesium Battery

Rechargeable magnesium (Mg) batteries attract lots of interest owing to their high theoretical volumetric energy density and low cost from the natural abundance of Mg. Additionally, Mg is less prone to dendrite growth during charging, which improves the battery safety. However, rechargeable Mg battery systems suffer from sluggish reaction kinetics on the electrodes and poor cycle life, greatly limiting their practical competitiveness. While most studies of rechargeable Mg batteries focus on the development of electrolytes and their feasibilities, the microstructure evolution of the Mg metal anodes during cycles is not fully unveiled. Furthermore, when using Mg metal as the anode, the excessive Mg may limit the overall energy density of the cells. Recently, anode-free battery systems were introduced to further improve the battery capacity. In this report, we investigated anode-free rechargeable magnesium batteries by electrodepositing Mg on a copper (Cu) current collector in an all phenyl complex (APC) electrolyte. Afterward, the microstructure evolution of the electrodeposited Mg after discharge/charge cycles was studied.The electrodeposited Mg on the Cu current collector with a current density of 2.25 mA/cm2 and a capacity of 1.5 mAh/cm2 shows a uniform distribution of Mg grains with an average grain size of 1.14 ± 0.06 μm. Subsequent Mg stripping with half the deposited capacity (0.75 mAh/cm2) was conducted at various current densities. Stripping with intermediate current density (0.75 mA/cm2) results in non-uniform discharge holes and possible local exposure of the Cu current collector, which could deteriorate the anode integrity. In contrast, the stripped electrodeposited Mg at relatively large (2.25 mA/cm2) and small (0.25 mA/cm2) discharge current densities show dense and uniform discharged holes on the surface. After prolonged discharge/charge cycles at a relatively large current density (2.25 mA/cm2), the electrodeposited Mg still exhibits a uniform surface morphology. In addition to cycling the electrodeposited Mg, a Mg-sulfur (Mg-S) full cell was also assembled with an anode of electrodeposited Mg on Cu and a sulfur/graphite cathode to explore the potential of anode-free rechargeable Mg-S battery. Figure 1

Investigations of a turbine pre-swirl system with high temperature drop efficiency through the design of a novel vane-shaped receiver hole

The pre-swirl system, a vital system responsible for supplying cooling gas to the turbine blades. However, the pre-swirl system involves rotor-stator matching and intricate power-heat conversion challenges, which has led to a bottleneck in the development of its temperature drop potential. This study investigates the traditional pre-swirl system structure to identify factors limiting its temperature drop performance. A novel design idea is proposed to enhance the temperature drop performance by reducing the power consumption in the pre-swirl system. Subsequently, the structure optimization and performance improvement for pre-swirl system are conducted through the design of four vane-shaped receiver hole models. To assess the effectiveness of these enhancements, the thermodynamic and aerodynamic characteristics of the pre-swirl system before and after optimizations are evaluated using numerical simulations. Finally, the system temperature drop characteristics equipped with optimal receiver holes are thoroughly evaluated by experimental test analysis. The findings reveal that the new type of pre-swirl system, featuring a leading-edge vane-shaped receiver hole design and the removal of the cover-plate cavity, surpasses traditional designs. It exhibits a remarkable 35.3 % improvement in the receiver hole discharge coefficient, a 39.7 % reduction in system entropy increase, and a 6.36 kW/(kg/s) decrease in specific power consumption. Significantly, experimental verification demonstrates a 10 % increase in the nozzle pressure ratio, the temperature drop of pre-swirl system increased by 53.6 % from 23.5K to 36.1K, and the temperature drop efficiency of pre-swirl system increased from 0.567 to 0.872. Therefore, this study offers valuable insights for the design of high-performance pre-swirl systems, contributing to the overall improvement of turbine efficiency.

A Comprehensive Design and Performance Assessment of a Reel-Type Blade Organic Waste Chopper Machine

The global issue of organic waste poses a serious threat to the environment and public health. With the increasing production of organic waste driven by population growth and urbanization, waste management systems worldwide are confronted with inevitable pressures. The decomposition process of organic waste generates methane gas, contributing not only to global climate change through the greenhouse gas effect but also posing risks of air and water pollution. The primary function of organic waste lies in its ability to become a valuable resource through recycling and composting processes. The potential use of organic waste as a source of renewable energy through biogas or biomass production also presents promising prospects. The objective of this research is to design a reel-type chopper machine for more optimal waste processing. The research method employed is engineering, involving non-routine design activities to create something new in both process and form. The results of the study show that the designed reel-type organic waste shredder has dimensions of 800 mm in length, 750 mm in width, and 1042 mm in height. The machine consists of four main components: the frame hopper, shredding cylinder, and discharge hole. The chopper machine has a power of 2.2 kW, a chopper capacity of 1 ton/hour, and a cutting length of 2–5 cm. The advantages of the shredded output from this reel-type chopper machine can accelerate the decomposition and fermentation processes of organic waste. The smaller and uniformly shredded particles provide a larger surface area for the activities of decomposing microorganisms. Additionally, reel-type machines are more efficient in processing materials with high moisture levels, such as wet branches or leaves. By ensuring optimal particle size, reel-type machines also enhance the efficiency of composting, as well as the production of compost briquettes and briquettes fueled by organic waste. Therefore, the role of reel-type organic waste shredder machines is crucial in maximizing the value of organic waste, accelerating the recycling cycle, and effectively reducing environmental impact.

Microstructure of Pure Magnesium and AZ31 Magnesium Alloy Anodes after Discharge/Charge Cycles for Rechargeable Magnesium Batteries

This study investigated the microstructure of pure magnesium (Mg) and AZ31 (Al—3 wt%; Zn—1 wt%) Mg alloy anodes after different discharge/charge cycles in an all phenyl complex (APC) electrolyte for rechargeable Mg batteries. When discharging the as-immersed Mg metal electrodes, the stripping morphologies of pure Mg and AZ31 Mg alloy electrodes are inhomogeneous with numerous discharge holes. In the subsequent charge stage, the plated Mg preferentially deposits along the circumferences of the discharge holes, which could be related to the distribution of Mg and Cl complex ions near the electrode surface after discharge. Later discharge/charge cycles on pure Mg show that both the plated Mg and the pure Mg substrate are stripped during discharge, resulting in an incomplete stripping of the plated Mg and a non-uniform electrode surface morphology after cycles. In contrast, AZ31 Mg alloy shows a higher stripping resistance than pure Mg, so the plated Mg is preferentially stripped during discharge. Near complete stripping of the plated Mg on AZ31 Mg alloy electrode results in a more uniform electrode surface morphology after cycles and a mitigated increase in the difference between the discharge and charge potentials.

Research and practice of high-speed spiral composite drilling technology in complex and weak coal seams

In response to the difficult slag discharge and low hole formation rate encountered in the Wangpo Coal Mine, a study was conducted on high-speed spiral composite drilling technology. This study was integrated with the performance characteristics of the ZDY6000LR-type high-speed pit rig, resulting in the design of drill bits in three different specifications: Φ110/63.5 mm, Φ95/60.3 mm, and Φ88/50 mm. Additionally, the study optimized the three-wing drill pipe's feed speed, rotation speed, and airflow volume. The industrial field test, conducted on the 3206 working face of the Wangpo Coal Mine, resulted in the design of three drill bit combinations that exhibited high strength and stiffness. This design improvement led to enhanced hole integrity, elevated slag removal efficiency, and extended service life for both the drill pipe and bit. The high-speed spiral composite drilling technology, alongside the supporting equipment, effectively addresses the challenges of slag discharge and nozzle top drilling encountered during operations. It significantly improves the deep hole drilling rate, achieving a drilling depth of over 100 m with a success rate exceeding 70%. This technology provides vital support for the extraction of gas from coal seams within the mine. Notably, the Φ95/60.3 mm screw pipe and its corresponding drill bit demonstrated the optimal holeforming effect, with an average hole depth of 111.2 m and a hole formation rate of 90.9%. These findings offer valuable insights for drilling operations under similar conditions of complex and weak coal seams.

Sensitivity of Laidback Fan-Shaped Hole Discharge Coefficient Under Internal Coolant Crossflow Conditions

Abstract An experimental study was performed on the discharge coefficients of laidback fan-shaped holes under different internal coolant crossflow orientations. The influence of the geometric and flow parameters on the discharge coefficient was investigated under flat plate conditions, where the pressure ratio ranged from 1 to 1.6. The results show that the film hole discharge coefficient is more sensitive to variations in the coolant crossflow under small pressure ratios. In comparison, the discharge coefficient is much less sensitive to the change of coolant crossflow under high pressure. Meanwhile, the length of the cylindrical section varied over the range of 1D–4D, and the length of the expansion section varied from 2D to 6D, where D represents the diameter of the film hole. The results show that the discharge coefficient is much more sensitive to the length of the cylindrical section than to the length of the expansion section. To quantify the sensitivity of the internal crossflow effects on the discharge coefficient, a low-ordered reduced model is proposed for the discharge coefficient of laidback fan-shaped holes. Both the geometric and flow parameters are considered in the model and give prediction errors within 5%.

Enhanced Jaya optimization in electrical discharge hole making of MoSi2–SiC composite with surface morphology analysis

Enhanced Jaya optimization in electrical discharge hole making of MoSi2–SiC composite with surface morphology analysis

Microstructure and the Plating/Stripping Behavior of Magnesium Metal Negative Electrode for Rechargeable Magnesium Batteries

Recently, rechargeable magnesium (Mg) battery systems attract lots of attention owing to their promising theoretical energy density, low cost from the natural abundance of Mg, and less dendritic growth of Mg during charging. Nevertheless, rechargeable Mg battery systems suffer from sluggish reaction kinetics on the electrodes and poor cycle life, which greatly limit their practical competitiveness. Most studies focus on the development of novel electrolytes and their feasibility for rechargeable Mg batteries, while the plating/stripping behavior of Mg metal negative electrode during the charge/discharge cycle is relatively less studied.Therefore, in this research, the platting/stripping behavior of the Mg metal electrode and the resultant surface microstructure after cycling were investigated in an all phenyl complex (APC) (PhMgCl + AlCl3 in THF) electrolyte. A Swagelok-type Mg||Mg symmetric cell was used in this study with an air-free transfer system to prevent the charged/discharged electrode from oxidation when moving to a scanning electron microscope (SEM) to observe the surface microstructure.When discharging the pristine pure Mg electrode, the stripping was found to be highly localized with numerous discharge holes on the electrode surface. Interestingly, in the subsequent charging stage, the platted Mg preferentially deposited along the circumferences of the discharge holes, which might be related to the distribution of Mg species right after discharge and the surface conditions of the discharged surface. Later discharge was found to preferentially strip the platted Mg and leave marks around the discharge holes. In addition to cycling on a pure Mg electrode, the platting/stripping behavior and the resultant microstructure of Mg metal deposited on a copper (Cu) current collector were also studied and will be discussed for potential anode-free Mg battery applications. Regardless of the platting/stripping conditions, no dendritic Mg was found during the charge/discharge cycles. Figure 1

Experimental study on crushing of concrete slabs by high-voltage pulse discharge

To investigate the effectiveness of high voltage pulse discharge (HVPD) in crushing concrete slabs, HVPD in-liquid tests were conducted in pre-drilled holes in three double-layer bi-directionally reinforced and twelve single-layer bi-directionally reinforced concrete slabs. The parameters that were varied in the tests included the concrete strength, discharge hole diameter and spacing, discharge voltage and number of copper wires discharged. The results showed that the explosion caused by HVPD using copper wires increased the crack width by more than 34.8% compared to that caused by the electrohydraulic effect. After 10 explosions caused by HVPD using copper wires, the single-layer reinforced concrete slab was split into several slabs by cracks to achieve the crushing effect. The single discharge energy, i.e., discharge voltage, had a significant effect on the crushing of concrete slabs, and the width of concrete cracks produced by a 100 kV discharge was more than twice that of a 40 kV discharge. The increase in concrete strength acted as a crack arrestor for the slabs, and the crack width of C20 concrete slabs increased by approximately 10% to 25% compared to C40 concrete slabs. The increase in crack width with increasing number of discharged copper wires decreased with increasing discharge voltage. The width of concrete cracks produced by the explosion of 60 copper wires compared to 30 copper wires increased by approximately 10% at 100 kV and by approximately 20% from 60 to 80 kV. The crack width of concrete slabs with discharge holes of diameter 40 mm increased by approximately 5% to 15% compared to concrete slabs with holes of 50 mm. Expressions for the relationships between the damage degree of the concrete slab (i.e., the width of the concrete cracks around the holes on the outside of the slab) and the key parameters such as the output voltage, the number of discharged copper wires, and the strength grade of the concrete were established based on the experimental results.

Ensuring the Stability of Channel Linings Under Unsteady Filtration

When assessing the stability of the slopes of the banks of reservoirs and channels, the filtration regime that occurs with a rapid decrease in the water level in the upstream, which is due to the nature of the operation of structures before floods, discharges, emergency situations, is of particular interest. A change in the water levels in the upstream causes a change in the position of the depression surface and the parameters of the filtration flow (pressure gradients, filtration rates and flow rates) in the coastal massif. At the same time, unsteady filtration occurs in the coastal massif and the stability of the slopes is reduced significantly due to the action of hydrodynamic forces directed towards the slope. The most reliable anchors of channel slopes in similar conditions are those that, under normal channel operation, when there is no groundwater support, the lining should exclude filtration from the channel, ie filtration losses of irrigated water, and if there is a backwater and with a rapid decrease in the water level in the channel, it should provide free access of the ground stream into the channel channel or its diversion in the other direction. This eliminates the occurrence of significant hydrodynamic pressures, and the destruction of the channel slope fasteners. The article presents the results of studies of 4 designs of channel linings operating under conditions of unsteady filtration. In the course of the study, we considered the following variants of structural schemes of linings. Fastening with combined deformation and filtration seams; fastening with self-collapsing seams; fastening with discharge tubular drains with water discharge into the channel; fastening with filtration and discharge holes arranged during the appearance of groundwater backup in the channel area. The results of calculating the stability of the fastening plates for overturning and surfacing are presented. According to the results of the calculation, the most acceptable fastening options are determined, their advantages and disadvantages are given. The proposed fastening design meets the above requirements and thereby ensures the strength and stability of the linings during the operation of the channel.

Study on the influence of constraint conditions on the slow cook-off response characteristics of melting and casting explosives

In order to study the slow cook-off test response characteristics of melt cast explosive and cast explosives under different constraint conditions, the heating characteristics, ignition characteristics and response law of melt cast B explosive and cast nitrate PBX explosive were studied by using self-designed slow cook-off test device when the ratio of discharge hole area to charge cross-section area Sh/Sc was 10%, 5% and 0%, respectively. The results show that in the slow cook-off process of two kinds of charge, the shell drain hole can effectively discharge gas or part of explosive before ignition. After ignition, the pressure can be released reliably, the increase of internal pressure in the shell can be restrained, and the intensity of response can be reduced; With the decrease of the size of the drain hole, the reaction intensity increases and the damage degree of the shell increases; When Sh /Sc =10, the combustion reaction takes place in both casting charge and casting charge; When Sh /Sc =5, the deflagration reaction occurs in the melt casting charge, which first burns and then deflagration reaction occurs in the casting charge; When Sh /Sc =0, the fusion charge and the casting charge have explosive reaction; Under the same constraint conditions, the safety of cast explosive is slightly higher than that of cast explosive.

TRANSITION FROM THE PLASTIC MODE OF DIAMOND GRINDING OF CERAMICS TO MELTING AND FEATURES OF THE MELTING OF INSTRUMENTAL CERAMICS

It is shown that the traditional method of estimating the specific energy capacity based on the ratio of grinding power to processing productivity does not provide an adequate solution, since with it the specific heat capacity of processing exceeds the specific heat capacity of melting ceramics by almost an order of magnitude, and therefore, any diamond processing of ceramics should immediately enter the plasticity regime, which is not really the case. Therefore, it is the application of a new approach to the assessment of the specific energy intensity of diamond grinding, taking into account the wear of the working layer of the diamond wheel, that makes it possible to assess the possibility of achieving the energy conditions for the transition of ceramic processing to the plastic mode.
 It is shown that the plastic mode occurs precisely when the specific energy capacity of grinding becomes close to the specific heat capacity of melting ceramics.
 It was found that similar to the processes during the thermal melting of ceramics, melting crusts are also formed in the discharge hole during electroerosion grinding. Quantitative analysis of melting products shows that a structure close to the fracture of the sample is formed in the discharge holes after melting, in which there is no oxygen.

Экспериментально-аналитические исследования критических условий факельного горения газов и паров криогенных топлив

The need to organize emissions of a large amount of gas arises in a number of technological operations related to the transportation, storage and processing of combustible gases, preparation and purging of containers, etc. The largest emissions occur during emergencies. For a correct assessment of the level of fire hazard and the choice of efficient ways to prevent fires, it is required to study in detail many defining parameters. First of all these are the limiting conditions for stabilization and extinguishing of diffusion flame of the torch. An analysis was made of the formation and stabilization conditions of a diffusion torch formed during the outflow of combustible gas from various gas discharge devices. On the basis of theoretical studies based on a single physical model, analytical expressions are derived. They describe the limiting conditions for the stabilization of turbulent diffusion torches in a wide range of changes in gas outflow conditions and parameters of the surrounding atmosphere. The proposed dependences allow to evaluate the complex effect of various factors (gas composition, gas discharge velocity and direction, size and shape of vents, wind speed, oxygen concentration in the surrounding space) on the parameters of turbulent diffusion torches. Within the framework of the study, the experimental regularities of stabilization and gas-dynamic extinguishing of turbulent diffusion torches are determined. These regularities make it possible to evaluate the influence of various factors (the degree of dilution of the combustible gas with an inert gas, the size and shape of the discharge hole, wind speed and oxygen concentration in the surrounding space) on the limiting conditions for stabilization of diffusion torches.

Simulation of Propeller Runner for Cylindrical Basin of Gravitational Water Vortex Power Plant

The gravitational water vortex power plant is an emerging technology of power generation from water vortex in a small amount. It can generate electricity in a low head of range (0.7-2m). This system is very simple and requires less keep-up. This research aims to develop the propeller type runner which gives optimum efficiency and cylindrical basin suitable for this propeller runner in GWVPP. The research has been conducted by developing a new propeller runner and cylindrical basin considering the top surface open as the atmosphere. Blade angle, discharge hole diameter of the basin, the position of runner, and rpm are optimized on CFD-based optimization. After the CFD analysis, the optimum blade angle was 43º, exit hole diameter of this basin was found 175 mm which is 20% of the basin diameter. The optimum height was found 785mm which is 65.42% of the total height. And the efficiency of the optimized system was 23.639 % at 40 rpm.

SmCl3’s effect on plasma electrolytic oxidation coating’s corrosion characteristics on AZ91D

Rare earth salt SmCl3 was added to the electrolyte to improve the corrosion performance of the AZ91D magnesium alloy plasma electrolytic oxidation (PEO) coating. The influence of SmCl3 on coating formation, morphology and performance was investigated. The results showed that adding SmCl3 can not only refine the discharge holes but also improve the coating’s formation efficiency and its’ combination with the substrate. Potentiodynamic polarisation (PDS) and electrochemical impedance spectroscopy (EIS) tests showed that the corrosion characteristics of the PEO coating were greatly improved with SmCl3’s addition. The corrosion current density decreased from 8.208 × 10−4 to 3.733 × 10−8 A cm−2 when the presence of optimum level of SmCl3 in solution (0.25 g L−1). Cyclic polarisation test indicated that the pitting corrosion of AZ92D was improved.

전북지역 조선시대 제철로의 구조와 제철유적 조성 배경

Of the 250 iron-producing sites distributed in the jeollabuk-do, 9 were from the Joseon Dynasty. Various remains such as smelting furnace, forging furnace, and waste place were investigated through excavation and investigation in the seasonal relics of the Joseon Dynasty. Among them, the smelting furnace is estimated to have a similar planar shape to a rectangular shape with rounded corners, and secondly, there is one discharge port on one long wall with a low terrain and about 19 small wind holes on one side of the long wall. In general, there are wind holes in the long wall opposite the discharge hole for the efficiency of the work. These melting furnaces are a type of so-called “box type furnace” and have similarities such as the planar shape and the presence of small-diameter wind holes from those of Japan, but their structures are generally different. This is intensively distributed in the southern part of the Korean Peninsula, including Chungju and Asan, and in particular, in the case of jeollabuk-do, all the smelting roads of the Joseon Dynasty surveyed so far are box type furnaces, so they are local. The produced iron is Bloomery iron, and it is highly likely that not only sand iron but also iron ore (titanium iron ore) was used as the raw material. It is believed that forging furnace was responsible for the function of refining and training-forging, which improved the quality of iron and made the tissue more dense than molding that produced the finished product. In particular, it is highly likely that it is Refining-forging, as there is a large amount of slag inside Okgye-dong Danya-ro, Namwon. On the other hand, referring to the literature records related to iron production, some of the 250 iron production sites distributed in Jeollabuk-do are believed to have been created and operated according to the iron tax receiving system and social changes during the Joseon Dynasty. In the early Joseon Dynasty, it is thought to be deeply related to the operation of cheolso and cheoljang(steel mills), and in the case of cheoljang, it is deeply related to the Cheoljangdohoe System, which took effect in the 7th year of King Taejong(1407). In the 18th year of King Seongjong (1487), as the Cheoljangdohoe System was abolished and Gakeupchenap system(each town arrears system) was implemented, production seems to have continued around iron reserves in jeollabuk-do. In the late Joseon Dynasty, as mining development and market revitalized, private production increased, and it is estimated that "hiding and producing” was prevalent when high taxes were imposed by the government to control this. The excavated iron production sites are believed to be deeply related to private production as their operation period is concentrated in the late Joseon Dynasty. In particular, considering that most of them were built in deep valleys, it is estimated that they were created by “hiding and producing”.

Micro Electrical Discharge Machining of Ultrafine Particle Type Tungsten Carbide Using Dielectrics Mixed with Various Powders.

Electrical discharge machining (EDM) is widely used to machine hard materials, such as tungsten carbide; however, the machining rate and surface quality are low. In this research, the effects of mixing electrically conductive carbon nanofiber (CnF), semiconductive silicon (Si) powder, and insulative alumina powder (Al2O3) at different concentrations in a dielectric fluid were studied by observing single discharge craters and hole machining performance in the EDM of ultrafine particle type tungsten carbide. Craters obtained using carbon nanofiber and alumina were much smaller than in oil-only conditions. In contrast, The results show that adding CnF significantly improved the material removal rate under all conditions. Si and Al2O3 powders only improved the machining performance at a high discharge energy of 110 V. Furthermore, improvement in surface roughness was observed prominently at high voltages for all the powders. Among the three powders, alumina was found to improve the surface roughness the most.

Effect of In2(SO4)3 on characteristics of Al–Li alloy MAO coating

ABSTRACT Micro arc oxidation (MAO) coatings were prepared on the surface of 2195 Al–Li alloy by adding different amounts of indium sulphate (In2(SO4)3) into an electrolyte consisting of silicate and phosphate. The surface, cross section, phase composition, and electrochemical experiments of MAO coatings were analysed. X-ray diffraction results show that the coating was composed of γ-Al2O3, α-Al2O3, and In2O3. The results show that after adding In2(SO4)3, the discharge holes on the surface of the coating were more uniform and the thickness was also increased. The corrosion resistance of MAO coatings was improved by the addition of In2(SO4)3.

Topology Optimization Design With Addictive Manufacturing Constraints for Centrifugal Impeller

Abstract Weight reduction of centrifugal impeller is of great significance for improving thrust-weight ratio of aero-engine. In this paper, the weight reduction design for a centrifugal impeller considering additive manufacturing constraints was carry out. First of all, reducing the structure weight by using the topology optimization method based on variable density method. Secondly, reconstructing the results of topology optimization based on the overhang angle, minimum length, connectivity and other additive manufacturing constraints, whose structure contains the self-supporting cavity, oval powder discharge holes and annular convex plate. Finally, adjusting the reconstructed model by using size optimization, which obtained an innovative hollow centrifugal impeller with both lightweight and high mechanical performance. The results indicate that the mass of the optimized centrifugal impeller reduces by 18.5% compared with the original model at the same stress level. The method and scheme can provide reference for the structural optimization design of aero-engine centrifugal impeller.