Discharge Hole Research Articles

Numerical Analysis of Two-Phase Flow in High-Speed Rotating Circular Tube

With the accelerating global adoption of electric vehicles, the automotive industry is about to reach a major turning point. In this context, we focused on centrifugal force and agitation for stable lubrication and delivery of oil inside the drive unit, which is indispensable to achieve the compact and high-speed motor technology that is so important. We quantitatively measured the ratio of the oil supply to the oil discharge by placing three discharge holes at each point of the circular tube. Based on the experiments, Ansys Fluent was used to reproduce the gas-liquid two-phase flow using the VOF method, and the rotational expression was analyzed numerically on a periodic boundary using MRF with fixed mesh and considering centrifugal and Coriolis forces. The percentage of discharge flow rate at each hole was evaluated for every 1000 [rpm] of rotation at different temperatures and different number of discharge holes. As a result, the results could not be perfectly reproduced because it was not clear whether the oil temperature in the high-temperature range was strictly controlled under the experimental environment, but the trend could be captured as the discharge from the first discharge hole became dominant at high rpm for both the 2-hole and 4-hole models. The trend could be captured.

Increasing the efficiency of the extruder in producing sunflower cake

The purpose of the research is to reduce the specific energy consumption of extruders in the protein feed preparation, namely a sunflower cake, and at the same time to increase productivity without product quality deterioration. The research objective is to develop a mathematical model that describes the performance of the improved extruder. As a result of the experimental and theoretical studies using experiment design methods, a mathematical model of the sunflower cake obtainment process was designed, it describes the performance of the improved extruder. The analysis of two-dimensional sections of the combination of X1 - X2 factors shows the nature of the response surface of an ellipsoid shape, X1 - X3, X2 - X3 are of a paraboloid, and the centers of the experiment are located in the investigated area, which allow determining rational parameters for combinations of these factors. As a result of a multifactorial experiment, the optimal values of the factors were determined: the mixture temperature at the exit from the extrusion auger of the matrix is 133.67 °C, the extrusion auger winding pitch is 7.58 mm, the area of the discharge hole of the matrix die is 323.89 mm2. With a combination of factor optimal values, it is possible to obtain high-quality sunflower cake with the highest extruder capacity, which is 0.87 t/h.

МОДЕЛИРОВАНИЕ ПАРАМЕТРОВ ШНЕКОВОГО ТРАНСПОРТЕРА-РАСПРЕДЕЛИТЕЛЯ

Loading grain crops into various containers is not easy due to the impossibility of filling the entire required capacity, uneven distribution of material, restrictions on the container design, etc. The article considers the design of a screw-type conveyor-distributor used for uniform loading. The device consists of a screw placed in a casing. From below, along the entire length of the conveyor-distributor, there is a discharge hole of a particular geometric shape. The study task was to obtain the parameters of the screw-type conveyor-distributor, to determine their effect on the production parameters of the screw with known parameters of the loading capacity for ensuring uniform grain loading. In the course of a computer experiment, screws with diameters of 100, 160, 200, 250, 315, and 400 mm were examined. While their speed changed from 50 to 600 min-1 at intervals of 50 min-1, the screw length varied from 1 to 14 m in increments of 1 m. The results obtained revealed acceptable diameters and speeds of screw-type conveyor distributors depending on the dimensions of the loaded containers to ensure uniform distribution. Using the example of a rectangular warehouse with a size of 14 by 20 m, the authors determined the technical characteristics of a screw-type conveyor-distributor and determined the appropriate geometric shape of the screw casing hole to ensure uniform grain distribution.

Influence of a stopping angle of a spiral coil on the operation of a spiral-screw dispenser

Dosing of dry concentrated feed to dairy cows is one of the most important tasks in the field of livestock mechanization. Devices that carry out volume dosing are more reliable and easier to be manufactured. Volumetric dispensers also include a spiral-screw dispenser – a special case of a screw dispenser. It is proposed to study the working process of the spiral-screw dispenser, namely the influence of a stopping angle of the last turn of the transporting spiral at the end of the discharge hole of the cylindrical casing. The paper indicates the method of determining and the value of the physical and mechanical properties of granulated feed. A laboratory installation on which it is possible to change the angle of installation of the spiral on the drive shaft is described. To study the effect of the stopping angle of the last turn of the transporting spiral on the accuracy of the formation of the feed portion, spirals with a diameter of 49, 73, 97 mm with different steps of 0.75, 1 and 1.25 of the diameter values were used. As a result of the experiments, it was revealed that the lowest coefficient of variation is 0.56 – 17.50%. And, accordingly, the greatest dosing accuracy is obtained when the last turn of the spiral stops at the position of 0°. That is, when the turn stops at the edge of the discharge neck in its lower part and this is typical for all sizes of spirals that were used.

Safety Evaluation of Arch Dam Subjected to Underwater Contact Explosion

The stability of an arch dam can be significantly damaged by an extreme underwater explosion. This study proposed a damage index for assessing the degree of local damage of an arch dam after the dam was subjected to an underwater explosion. The damage index was applied to assess local damage at the middle part of the dam, surcharge holes, and abutment. A model was developed to evaluate the stability of the entire dam based on the spatial distribution of damage and the damage on the base interface. Results showed that local explosion damage at flood discharge holes or abutments might cause instability of the arch dam. When the contact explosion action location is on the abutment, it only needs 310 kg to cause the overall damage of the arch dam, while when the action location is on the middle part of the dam, the quantity of explosive required is 2800 kg.

Study on Influencing Factors and Laws of Fuel Injection Consistency of Common Rail Injector

In order to study the influence of parameters of common rail injector internal components on cycle injection consistency, its simulation model is established by AMESim, and the model is validated by the experimental injection rate data. The effects of solenoid valve spring preload, gag bit lift, fuel discharge hole diameter, fuel inlet hole diameter, needle valve lift, needle valve preload and nozzle diameter on the change of injection quantity under different operating conditions are studied by simulation method, and the impact weight of each parameter on fuel injection consistency is analyzed. The results show that the preload of solenoid valve, fuel discharge hole diameter, oil inlet hole diameter, needle valve lift and nozzle diameter are the main parameters affecting the consistency of cycle injection. The percentages of five parameters influencing on the consistency of cyclic injection are 8.68-16.84%, 11.41-23.68%, 17.2086-37.74%, 12.772-18.34% and 9.69-37.27% respectively.

RANCANG BANGUN KOMPOSTER AEROB DAN ANAEROB UNTUK MENGURANGI SAMPAH ORGANIK RUMAH TANGGA

This objective of this study was design and manufacture a simple drum compost reactor (composter) to be able to process organic waste into compost so as to reduce the problem of organic waste towards generation-z let’s go organic in the orphanage sinar indah cahaya bersama. The method used was engineering or modification, design research activities that are not routine so that contributions are generated in the form of processes and products. The result of the composter was vertical type aerobic composter drum without mixing system with parts up cover, composting room, filter, filter support posts, leachate chamber (liquid organic fertilizer), pipes and air vents covered with gauze, solid compost discharge holes and faucet dispensing liquid organic fertilizer.

Numerical Study on Discharging Characteristics of Entangled Cluster of Particles in Particle Bed

To better understand the flow features of the particle cluster in a particle bed, discharging of the particle entangled cluster is simulated by the discrete element method (DEM). The particle entangled cluster is composed of eight particles connected by rigid bonds, and the simulated entangled cluster models are divided into two types: axisymmetric u-particles and distorted z-particles. The simulation starts with the closed discharge outlet, and the bonded clusters with different IDs are randomly added from the entrance section. The particles fall freely and accumulate freely in the particle bed. The discharge hole opens after all the particles are stationary for a period. Then, the particles are discharged from the particle bed under gravity. The discharging process has time-dependent bulk-movement behavior. There is not much mixing between layers on the boundary. The vertical end not only makes the packing loose but also intensifies the interaction between particles due to entanglement. Consequently, the discharge features of particle entangled clusters of different included angles were quantified. The results show that the particle discharging speeds depend on the entanglement angle (α of u-particles and η of z-particles) and discharging outlet diameter. A large included angle may play the role of retarding or inhibiting the discharging flow rate. Therefore, the entanglement of particle components also always plays the key role of retarding the discharge.

Design of A Micro Hydro Power Plant Based on The Vortex Flow of Water

This research focuses on the gravitational creation of a water vortex stream, which is a novel technique in hydropower engineering. The water enters a wide straight inlet and then through a vertical conical tube, creating a vortex that exits at the shallow basin's centre floor. The blades of the turbine can spin in the vortex, which generates electricity from a generator. The gravitational vortex turbine is the name for this kind of turbine. The turbine is driven by the vortex's dynamic force rather than the pressure differential. Since no discretization of the flow domain is needed, this study relies on simulation to provide the specifics of water vortex creation. The computational fluid dynamics (CFD) models' boundary conditions are added depending on the experiment configuration. Two different hole sizes for water discharge were tested in two different environments. The first condition's effect shows that the vortex heights in the experiment and CFD agree. The final vortex height of the CFD model differs from the experiment outcome in the second condition. More turbulent flow has set in as the discharge hole becomes larger, creating more errors in the CFD model's prediction of water vortex formation.

Application of qualitative trend analysis in fault diagnosis of entrained-flow coal-water slurry gasifier

Entrained-flow coal-water slurry (CWS) gasification is a clean and efficient energy utilization technology and it was difficult to avoid misoperation during gasifier operation process. Qualitative trend analysis (QTA) is a data-driven method based on process history, and has been widely used in process monitoring and fault diagnosis. In this study, a suitable on-line basic primitive sequence processing method combining QTA and the extended sliding window trend extraction (SWTE) method is developed for the operation of entrained-flow CWS gasifier. Based on the optimized method, trend extraction and primitive sequence processing on three sets of data, i.e., gasifier temperature, gasifier pressure, and slag discharge hole pressure difference, were performed in this study. The optimized method could be effectively applied to the real-time monitoring and fault diagnosis of entrained-flow gasifier since its output was simple and accurate.

Influence of pumping effect on axial rotating holes

Rotating holes are widely used in jet engine internal air systems as an important kind of throttling element. The flow characteristics of rotating holes are of great importance in the design of the internal air system. This paper aims to investigate the influence of pumping effect on the flow characteristics of axial rotating holes. Pumping effect refers to the flow phenomenon induced by a rotating plate which characterized by a radial outflow. There are altogether two types of holes considered in the paper: round hole and square hole. A 1/25 (14.4-degree) sector model is used to carry out the numerical investigation using the commercial software ANSYS CFX. In the simulation, the SST turbulent model is used. Meanwhile, a non-rotating method using the relative frame of reference is used. In the non-rotating method, an initial incidence angle is given at the inlet instead of setting the plate to be rotating, thus the pumping effect induced by the rotating plate can be eliminated. The non-rotating method results are compared with the conventional reference frame results to investigate the influence of pumping effect. The results show that due to the influence of the pumping effect-induced radial outflow, the theoretical two-dimensional incidence angle becomes three-dimensional, which has negative effects on the hole discharge coefficient. At the same time, due to a larger circumferential length, square holes will undermine the pumping effect, thus has a higher discharge coefficient than the round holes.

Deep deformations of the upper stream of a low-pressure reservoir

The article presents the results of the analysis of the deep deformations of the Amu Darya riverbed in the upper reaches of the low-pressure reservoir. The analysis of the combined transverse profiles of the riverbed in different sections of the upper reaches of the Takhiatash reservoir showed that the coastal zones are most intensively silted up. At the same time, the core zone with the highest flow rates is very weakly declared. The height of the silting layer along the length of the upper stream increases in the direction of the dam. The silting area extends upstream for a length 2-3 times longer than the length of the soundings section, which is 17.5 km. To ensure the normal operation of the hydraulic system, it is recommended that conditions should be created for a normal and stable approach of the flow to the hydraulic system, which should be ensured by maneuvering the shield holes. To do this, it is necessary to create conditions for the erosion of the left-bank spillway by increasing the water flow through the extreme left-bank discharge holes. Flushing of the upper left-bank section of the river should continue until the optimal width of the leading channel is reached, which provides the main flow of the stream in front of the structure. It is proved that the formation and development of sediment deposits on the right bank between sections 8-10 leads to a change in the flow correction and creates conditions for the formation of shoals in front of the regulator of the Kizketken channel, which can complicate the operation of the water intake zone. Therefore, it is necessary to take measures to prevent the development of the right-bank channel, and the development of the channel should go from the main channel. As shown by monitoring operating mode Takhiatash waterworks, in the Takhiatash district waterworks intensive processes the channel formation, which has a strong influence on the operational mode of the dam, especially in the operation of the water intakes flushing of sediments, skip flood costs through the shields of the dam and the stability of structures.

Дослідження режимів роботи циклону з проміжним відведенням осадженого пилу

Goal. The problem can be solved in research by studying the effect of the ratio of the volume of gas passing through the dust unloading holes to the amount of gas passing through the tangential inlet to the hydraulic resistance and cleaning efficiency in the cyclone with intermediate removal of precipitated dust. Actualіty of the work is that the establishment of the optimal ratio between the flow of air sucked through the dust holes and the total air flow in the cyclone with intermediate removal of deposited dust will obtain the highest efficiency of this type of device while reducing hydraulic resistance. The method is that to determine the hydraulic resistance and cleaning efficiency using CFD - programs in the CAD - program was built a cyclone model with intermediate removal of deposited dust, the design of which is presented in [5] by the method according to [6]. Results. The optimal ratio between the flow of air sucked through the dust unloading holes and the total air flow in the cyclone with the intermediate removal of deposited dust for different connection schemes of the device. Scientific novelty. For the first time with the help of theoretical researches the optimum ratio between the expenses of the air sucked out through dust unloading openings and the general expenses of air in a cyclone with intermediate removal of the deposited dust is established. Practical significance. The use in a cyclone with intermediate removal of deposited dust, the optimal ratio between the flow of air sucked through the dust discharge holes and the total air flow allows to obtain higher efficiency of air purification from dust at lower energy costs.

Directional fracturing excavation technology based on liquid CO2 phase transition in freezing shaft sinking

ABSTRACT In the tunneling of frozen soil section of shaft sinking by freezing method, the traditional air pick excavation has large consumption of pick and drill rod, low excavation efficiency, and high labor intensity. The drilling explosive blasting method has a poor working environment and potential safety hazards. The safe and efficient excavation of frozen soil section is a difficult problem faced by freezing method shaft sinking. In this paper, a directional fracturing method by liquid CO2 phase change for freezing shaft sinking is proposed. Based on the traditional CO2 phase change fracturing device, a liquid CO2 phase change fracturing device with directional function is designed. It can not only fully crush and weaken the frozen soil in the shaft, but also can not disturb the shaft wall structure. The liquid CO2 phase change directional fracturing technology is firstly applied to the assisted tunneling in freezing shaft sinking. The field test results indicate that the directional liquid CO2 phase change generator has a good directional fracturing function. There are many obvious cracks formed around the directional fracture drilling hole, and the cracks are all extending toward the center of the protection circle. The angle between the two outermost cracks is close to the phase angle of directional discharge hole of liquid CO2 phase change generator. According to the statistics of field construction, the average daily excavation speed of frozen soil section is increased from 1.67 m/d to 2.45 m/d after directional fracturing by phase change of liquid CO2. Compared with explosive blasting weakening, liquid CO2 phase change fracturing has the advantages of no spark in the phase transformation process, easy control of pressure, convenient storage and transportation, simple operation, and relatively safe construction process. Liquid CO2 phase change fracturing shows a good application prospect in some fields which have high safety requirements. It is expected to be popularized and applied in slope excavation, tunnel chamber excavation, and other fields in the future.

Improving the Efficiency of the Separation Process of Liquid Heterogeneous Systems

For efficient separation of liquid heterogeneous systems in oil and gas industry, various types of sedimentation tanks, separators, hydrocyclones, etc. are used, the principle of which is based on gravitational and centrifugal separation of heterogeneous masses of different densities. In order to ensure the best hydrodynamic conditions for the process of suspensions separation in a hydrocyclone and to prevent clogging of the discharge hole, an apparatus that contains only the cylindrical part of the housing is proposed. The presence of a taper displacer ensures the maintenance of optimal hydrodynamic conditions along the entire length of the apparatus, from the inlet to the discharge hole. The taper of the displacer affects the distribution profile of the tangential velocities of the fluid in the near-wall region, ensuring the constancy of the velocity profile along the radius and the specific flow rate over the cross section of the apparatus. Basing on the results of studies carried out on a real product (a mixture of PVCR with water) at a pressure and flow rate corresponding to the production ones, an industrial prototype of the apparatus has been designed and produced.

Investigation of the dependence of the axial force acting on the rotor of a vertical centrifugal pump on the area of the discharge holes of the impeller

The article describes a vertical centrifugal pump with a bearing Assembly in the upper part of the rotor. It is shown that for certain values of design parameters, the influence of the so-called discharge holes in the impellers can significantly affect the axial force acting on the rotor, and for certain parameters, for example, with a large weight of the rotor, this influence is insignificant and the manufacture of such impellers is impractical.

Research on the optimization of stress relief holes applied in blanks used for body-in-white stamping parts with complex asymmetrical shapes

Increasing the degree of deformation when stamping body-in-white parts with complex asymmetrical shapes can be achieved by optimizing the discharge holes in the flange of the blank. For this purpose, the numerical simulation of the deep-drawing process with finite element is used. Considering the circular shape of the unloading hole, the expanded shape of this hole is determined using the FEM, taking into account the safety limit given by the final shape of the stamped part. To check that the deformation that occurs at the edge of the expanded hole not cause cracks in the part the area with deformations whose values exceed the permissible limit is delimited. The arc that stretches this area along the contour of the expanded hole is divided into a convenient number of equal segments. The points at the end of each segment are then translated on the edge of unloading hole by measuring the distances between these points on the expanded blank hole. Using a mathematical modelling of the allocated points on the contour of the unloading orifice, the corrected shape of this orifice is determined, which is perforated in the flat blank.

Investigation on the Radial Heat-Transfer of Pumping Secondary Flow in Semiclosed Rotating Disk Cavity

Abstract This study investigates the mean flow and radial heat-transfer behaviors in semiclosed rotating disk cavity within the canned reactor coolant pump. The flow in the semiclosed cavity contains the Stewartson type flow at inner region and the Batchelor type flow at outer region. The heat is radially transported from the outer rim of the semiclosed disk cavity to discharge-hole through the nondirect discharge (ND) portion of the superimposed flow from inlet. The effects of rotating Reynolds numbers, cavity aspect ratio and radial location of discharge-hole on the discharge ratio, pumping mass flow rate, local wall shear stress and radial heat-transfer coefficient are examined in the semiclosed rotating cavity flow, respectively. Based on the radial heat transfer behaviors of pumping secondary flow, an equivalent thermal network is proposed and validated by experiments, which can effectively predict the radial temperature distribution from the discharge hole to periphery with the viscous-heating and nonisothermal effects.

基于先验知识的Kmeans聚类生物质颗粒缺陷检测方法

Biomass particle is one of the most important solid briquette fuels for agricultural and forestry biomass energy. Temperature, pressure, moisture and discharge holes are important factors to control biomass particle forming. The inappropriate setting of the parameters or blocking of the discharge hole will lead to the defects of the biomass particles, such as too short or poor roundness or pits or cracks. In order to detect these defects automatically, this paper proposes a method based on K-Means with prior knowledge. Firstly, the inner boundary tracking region detection algorithm and filling algorithm are combined to extract the regions in the backlight image. The regions are divided into debris, independent biomass particle regions and adhesive biomass particle regions. Secondly, K-Means with prior knowledge is used to segment the adhesive regions to get the independent biomass particle regions. Finally, the features of the biomass particles are extracted to judge the type of defects. The proposed method has been tested on images acquired from the vision system of the ring roller pellet mill. Experimental results show the efficiency of the proposed method in high detection accuracy and short detection time.

Side ratio effects on flow and pollutant dispersion around an isolated high-rise building in a turbulent boundary layer

Large-eddy simulations were performed to investigate side ratio (SR) effects on flow and dispersion around an isolated high-rise building. Four cross sections were considered with SR ranging from 0.25 to 1.5. Three pollutants were released from the ground; the first source (P1) was upwind of the building, and the other two (P2 and P3) were downwind. Reattachments on the side and top surfaces were observed for SR = 1.5. As SR decreased, the recirculation area behind the building increased and vortex shedding strengthened. The dispersion area of pollutant P1 nearly coincided with the primary separation region at ground level because its source location was inside the primary separation region. More of pollutant P2 accumulated near the leeward wall because the discharge hole was located inside the recirculation region behind the building for all simulations, and large SR values had high P2 concentrations because of the weak vortex shedding strength. Pollutant P3 (whose source was far from the building) exhibited different distribution patterns because of different recirculation sizes; it was blown directly downstream for SR = 1.5 and 1.0, whereas more was transported back toward the leeward wall for SR = 0.25. An analysis of the probability density functions of instantaneous concentration indicated that positive fluctuations of the concentration occurred more frequently near source locations; the opposite held in relatively low-concentration areas. The extremely high positive fluctuations reached 15 times the standard deviation for the second mode.