Optimum Inclination Angle Research Articles

The length of distal skin incision of the postero-lateral approach affects the cup inclination during the total hip arthroplasty

Aim: The primary aim of the study was to determine whether the length of the distal skin incision of the posterolateral approach affects the cup inclination during total hip arthroplasty (THA).
 Material and Method: In this study, a cohort of 71 consecutive patients who performed between January 2017 and December 2021 with unilateral THA using a posterolateral approach was retrospectively assessed. Two groups were formed according to acetabular cup inclination with normal anteversion angle. There were 56 hips in the inside group and 17 in the outside group. A curvilinear skin incision of around 13 cm was performed. Component position evaluation was carried out through a radiographic assessment of the acetabular component on an anteroposterior pelvis radiograph. The rate of an outlier was compared between groups according to the safe zone defined as 30° to 50° of inclination and 5° to 25° of anteversion, which was described by Lewinnek et al. 
 Results: No significant difference in the average total incision length was found between the two groups (p=0.207). While the average distal incision length was 7.91±0.62 cm (range, 6.8-9 cm) in the inside group and 6.37±0.21 cm (range, 6-6.7 cm) in the outside group. According to ROC analysis, a patient with ≤6.7 cm of the distal length of incision (DLI) was 5.71 times more likely to be outside than a patient with >6.7 cm of DLI. Seventeen hips (23.3%) were found outside the safe range. Substantial differences were observed regarding radiographic cup inclination between the two groups (p=0.0001). In the inside group, the average cup inclination was 44.11°±3.44° (range, 37°-50°), whereas, in the outside group, it was 55.41°±2.5° (range, 52°-59°). However, there were no significant differences in the average radiographic cup anteversion between the two groups (p=0.960). Although 11 of 17 (64.5%) patients were classified as obese (BMI ≥30) in the outside group experienced higher rates of inaccurate cup orientation, logistic regression analysis showed that the individual effects of obesity on the occurrence of the inaccurate cup position were not observed (p=0.884). One posterior hip dislocation occurred after one month postoperative in the outside group. 
 Conclusions: Longer distal portion of the skin incision of the posterolateral approach should be performed to achieve optimal operative inclination angles of the acetabular cup during THA. The surgeon must have no hesitation in extending the distal skin incision when adopting the posterolateral approach.

Solar flat plate collector enhanced by two reflectors: optimum tilts of reflectors

Introduction. In some solar concentrating system applications, in which the incoming sunlight is augmented by using commercial flat plate reflectors placed on different sides of the planar collector, it is very important to choose the optimum tilts of boosters (attached edge-to-edge on the top and bottom sides of the solar collector) for each month, to enhance their received solar irradiation over the year in the southern Algeria. The novelty of the proposed work consists of the development of a novel mathematical model in which the reference of the reflector’s tilt angles is the collector plane, and optimal tilts are optimized on the average day of each month. Purpose. This paper proposes a novel analytical model of two identical planer reflectors, placed on the top and bottom of a latitude tilted flat plate solar collector, for optimizing their optimal inclination angles during the daytime throughout the year in Ouargla city, southeast of Algeria. Methods. Optimal tilt angles of reflectors were obtained by searching for the optimum captured solar irradiation on the collector’s surface from each reflector in the representative day of each month of the year. After that, the obtained tilts were used for calculating incoming solar irradiation on the received area and comparing them to the solar collector without reflectors. Results. The findings of this paper showed that the reflector’s inclination angles were variable from one month to another in which the upper reflector’s tilts reached its maximum in June and minimum in December, contrarily for the lower reflector. Again, an increase of 28.05 % in the daily received solar irradiation on the collector surface with reflectors compared to the conventional one.

Effect of mitigation on the catastrophic failure of storage tanks

This work investigates the effect of incorporating mitigation techniques on the catastrophic collapse of above-ground storage tanks in terms of dynamic pressures and overtopping fractions using Computational Fluid Dynamics (CFD). Catastrophic Overtopping Alleviation of Storage Tanks (COAST) and Mitigation of Tank Instantaneous Failure (MOTIF) protection measures are implemented. COAST is a deflector fitted to the top of the bund wall that is a structure surrounding a storage tank and MOTIF is a baffle fitted inside the storage tank. An optimisation study has been conducted to select the optimum mitigation technique and the optimum inclination angle of COAST. Subsequently, the effect of incorporating mitigation techniques using different capacities and shapes of bund wall is investigated along with the effect of using various heights of the fluid within the tank. Results show that COAST alone is more effective than combining the two mitigation techniques and the optimum inclination angle giving the lowest dynamic pressures and overtopping fractions is 80°. COAST significantly reduces the overtopping fractions ranging between 93% and 98% for the various capacities investigated. The highest reduction corresponds to a bund wall capacity of 200% of the capacity of the tank. The effect of COAST in reducing the overtopping fractions is more significant for circular shapes than square, rectangular, and triangular walls. Regarding the height of the fluid, COAST is more effective for tall tanks compared to middle and squat tanks.

An energy analysis of translucent concrete embedded with inclined optical fibers

Translucent concrete (TC) is a kind of energy-efficient building envelope, which is able to transmit daylight into the interior of a building efficiently with improved thermal performance. Previous research shows that a kind of novel TC embedded with inclined optical fibers (OFs) is promising to achieve better climate-responsive transmittance and improved energy-saving potential compared with conventional TC. However, the newly proposed TC differs from traditional one in both light and heat transfer processes, and its distinctive optical and thermal performance have not been fully revealed. To bridge this knowledge gap, an improved optical and thermal model of the novel TC was developed and validated with experimental data. A parametric study was conducted to reveal the effects of optical fiber inclination angle and numerical aperture (NA) on the TC. The results show that the climate-responsive transmittance of TC can be improved by inclining OFs, and this can serve as a feasible method for TC transmittance adjustment especially when OFs with high NA values are not available or not cost-effective. The optimal optical fiber inclination angle is about 10° for a south-facing TC wall in Beijing, which is able to reduce building energy consumption by about 4.98% to 21.88% depending on the coefficient of performance (COP) of heating, ventilation and air conditioning systems.

Biomechanical evaluation of a short-rod technique for lumbar fixation surgery.

Objective: The purpose of this study was to analyze the stability and instrument-related complications associated with fixation of the lumbar spine using the Short-Rod (SR) technique. Methods: Using finite element analysis, this study assessed the stability of a bilateral lumbar fixation system when inserting the pedicle screws at angles of 10°, 15°, and 20° to the endplate in the sagittal plane. Using the most stable construct with a screw angle, the model was then assessed with different rod lengths of 25, 30, 35, and 45 mm. The optimal screw inclination angle and rod length were incorporated into the SR model and compared against traditional parallel screw insertion (pedicle screws in parallel to the endplate, PPS) in terms of the stability and risk of instrument-related complications. The following parameters were evaluated using the validated L4–L5 lumbar finite element model: axial stiffness, range of motion (ROM), stress on the endplate and facet joint, von-Mises stress on the contact surface between the screw and rod (CSSR), and screw displacement. Results: The results showed that the SR model with a 15° screw inclination angle and 35 mm rod length was superior in terms of construct stability and risk of complications. Compared to the PPS model, the SR model had lower stiffness, lower ROM, less screw displacement, and lower stress on the facet cartilage, the CSSR, and screws. However, the SR model also suffered more stress on the endplate in flexion and lateral bending. Conclusion: The SR technique with a 15° screw inclination and 35 mm rod length offers good lumbar stability with a low risk of instrument-related complications.

Effects of mechanical vibration on the heat transfer performance of shell-and-tube latent heat thermal storage units during charging process

Mechanical vibrations are unavoidable in thermal systems at certain times, but they do not only have a bad effect. This paper presents the first pioneering study of the effect of vibration on the heat transfer performance of a horizontal tubular heat exchanger. Through numerical simulation methods, by applying mechanical vibrations of different vibration frequencies and vibration amplitudes, the heat transfer enhancement effect of phase change material (PCM) under vibrational conditions are fully revealed. The results show that, under lower vibration frequencies (ω = 10 ∼ 20 Hz), which can significantly promote the mixing of melted PCM and melting heat transfer rate during charging processes. However, this heat transfer enhancement begins to weaken in the range of medium to high vibration frequencies. For all amplitudes, the heat transfer enhancement is markedly stronger than that of frequency, which is linked directly to the magnitude of the amplitude value. Furthermore, the effect on heat transfer enhancement has been discussed when there is an inclination of the vibration axis to the direction of gravity. When the inclination angle is varied from 0° to 90°, the contribution to heat transfer enhancement is greatest at θ = 30°, which is optimal inclination angle. This paper could fill the knowledge gap regarding the thermal performance of heat exchangers with different geometries under mechanical vibration and provide some guidance for future practical applications.

Indoor MIMO-VLC Using Angle Diversity Transmitters.

In this paper, we, for the first time, apply angle diversity transmitters (ADTs) to enhance the performance of multiple-input multiple-output visible light communication (MIMO-VLC) systems. The ADT is designed to consist of one center light emitting diode (LED) and multiple inclined side LEDs. We calculate the line-of-sight (LOS) channel gain of the MIMO-VLC system using ADTs and further derive the average achievable rate of the system. We show that the average achievable rate is related to both the inclination angle of the side LEDs and the spacing between two adjacent ADTs in the MIMO-VLC system. Simulations are conducted to verify that the average achievable rate of the ADT-enhanced MIMO-VLC system can be maximized by setting the optimal inclination angle of the side LEDs and the optimal spacing between adjacent ADTs. The obtained results further show that the average achievable rate of the ADT-enhanced MIMO-VLC system can be greatly improved when there are more LEDs in each ADT. Specifically, a substantial 42.9% average achievable rate improvement can be achieved by using the optimized ADT in comparison to using a conventional non-angle diversity transmitter.

ANALISIS PENGHEMATAN BIAYA LISTRIK DI KANTOR DINAS KETENAGAKERJAAN DAN ESDM PROVINSI BALI PASCA TERPASANG PLTS ATAP 40 KWP

PLN's electricity sales in 2020 reached 234.5 TWh, while electricity consumption in Bali Province throughout 2020 was 4.9 TWh. In this study, PLTS roof supporting parking at the Office of the Manpower and ESDM Office of the Province of Bali is used as a location for installing PLTS in the use of new and renewable energy which has an impact on saving electricity bills and reducing CO? emissions. PLTS is installed with a total capacity of 40 kWp with an on grid configuration. Based on the research results, the simulation uses HelioScope software using two scenarios. In scenario 1 with an optimal inclination angle of 14.79°, the potential for energy production is 59.251,00 kWh/year, while in scenario 2 with an optimal tilt angle of 6.35°, the potential for energy production is 59.251,00 kWh/year. PLTS production from June to December 2021 is 35,287.90 kWh with savings on electricity bill costs of Rp. 67,640,740.00 and is able to reduce total CO? gas emissions by 27,233.33 kg CO?.

Theoretical Research of the Potato Harvester Lifting Plowshare to Reduce Yield Losses and Soil Erosion

Introduction. The potato harvester operation quality depends not only on the design features, but also on the method for harvesting of potatoes. Cultivation of potatoes involves the implementation of a set of measures aimed at improving and preserving the quality of commercial products when harvesting of potatoes. In this regard, to reduce yield losses and prevent wind erosion of soil, a unit and method for harvesting of potatoes is proposed. To reduce the number of clods commensurate with the size of tubers, there are installed ripper tines ahead of the potato harvester tool. The aim of the work is to conduct a theoretical research of the tool of the potato harvester to reduce yield losses and soil erosion. Materials and Methods. The lifting plowshare operation has been analyzed. Its angle to the horizon determines the least displacement of the lifting plowshare, the minimum resistance to the soil layer movement and optimal height of lifting soil mass. The optimal value of the plowshare inclination angle has been determined taking into account the condition that the back pressure of the soil layer should be minimal. Results. There has been proposed a mathematical dependence for determining the optimal value of the angle of plowshare inclination, which determines the minimum value of the soil layer back pressure acting along the plowshare. As a result of the research, there have been plotted graphical dependences of the optimal value of the plowshare inclination angle on the coefficient of soil friction on the plowshare and dependences of the height of a soil layer lifting with the plowshare on the inclination angle optimal value at a fixed plowshare length. Discussion and Conclusion. In carrying out the theoretical research of the potato harvester plowshare, the soil type and coefficient of a soil layer friction on the plowshare were taken into account. There has been determined the optimal angle of plowshare inclination to provide optimal breaking down of soil with minimum soil bulldozing, thus ensuring reduction in yield losses.

Evaluation of the grinding process utilizing an auxiliary compressed air jet on cleaning the grinding wheel surface

Grinding is one of the most complex and precise machining operations, with the performance of the grinding wheel being heavily reliant on its surface conditions. Removed chips tend to be forced back to the wheel surface due to the intense heat generated in the grinding zone. The loaded chips block the wheel's grinding capability, resulting in increased grinding force and temperature, wheel chatter, and workpiece thermal degradation. To solve these problems, this research examines the effectiveness of an auxiliary compressed air jet system during the grinding of spk tool steel with an alumina grinding wheel to clean the wheel surface of lodged chips and then the percentage of wheel loading for different tests will also be evaluated. The compressed air nozzle was examined from a variety of perspectives (0, 30, 45, and 60). Grinding with and without a cleaning system, as well as conventional cutting fluid, were also employed as comparisons. In certain output results, input parameters such as grinding wheel speed (20 m/s), cutting depth (20 m), and feed rate (100 mm/s) were maintained constant. When compared to other experiments with different cleaning nozzles, the optimal inclination angle of 45°, which allows the maximum air to reach the interface between the wheel surface and chips, removed chips by pushing them off the wheel surface. Other cleaning nozzles, such as 0°, 30°, and 60°, were less successful. The incidence angle of 45° produced the best results in terms of surface roughness, diametrical grinding wheel wear, G-ratio, tangential forces, specific energy, and wheel loading analysis. Image processing was used to detect and identify chips accumulated between abrasive grains on the wheel surface. To better understand the structure of the wheel and workpiece surface, optical and scanning electron microscopy pictures were taken and analyzed. This research adds to our understanding of the grinding wheel loading mechanism and its dynamics.

Design of inclined omni-directional reflector for sidewall-emission-free micro-scale light-emitting diodes

Micro-scale light emitting diode (µLED) reduces the front self-luminous display area by orders of magnitude, which brings the increase of sidewall emission and the resulting crosstalk between adjacent sub-pixels of displays. Reflector coating on the µLED’s sidewall is effective for the collection and utilization of side emission light. However, the existing multilayer periodic dielectric mirrors are undesirable for all angular reflection. In this paper, an omni-directional reflector (ODR) is designed for the µLED display pixel to effectively utilize light leakage from the sidewall emission and improve the total light extraction efficiency (LEE). The designed ODR is insensitive to the angular distribution of the incident light, and has the capability to reflect the light reaching the µLED’s sidewall into the escape cone for front emission. By introducing the two-dimensional finite-difference time-domain method, the µLED laminated structure is established to analyze the sidewall emission with an optimal inclination angle. By introducing the ODR for the inclined µLED pixel, the overall LEE can be increased by 2.24 times and the sidewall emission is reduced by 99.6% compared with conventional vertical µLEDs. Simulation and experimental results are in good agreement. The proposed ODR is expected to achieve the increase of LEE and sidewall-emission-free µLED displays.

An estimation framework of regional rooftop photovoltaic potential based on satellite remote sensing images

This paper proposes a comprehensive framework for estimating the regional rooftop photovoltaic (PV) potential. The required rooftop information is extracted from Gao Fen-7 satellite images. In particular, the rooftop area is obtained using a semantic segmentation network. The azimuth and inclination angles are calculated based on the digital surface model. In addition, to improve the accuracy of the economic evaluation, buildings are divided into commercial and industrial buildings and residential buildings. Based on the difference in the roof inclination, the rooftops can be divided into flat roofs, on which the PV panels are installed with the optimal inclination angle, and sloped rooftops, on which the PV panels are installed in a lay-flat manner. The solar irradiation on the plane-of-array is calculated using the isotropic sky translocation model. Then, the available installed capacity and generation potential of the rooftop PV is obtained. Finally, the net present value, dynamic payback period, and internal rate of return are used to evaluate the economic efficiency of the rooftop PV project. The proposed framework is applied in the Da Xing district of Beijing, China, with a total area of 546.84 km2. The results show that the rooftop area and available installed capacity of PV are 25.63 km2 and 1487.45 MWp, respectively. The annual rooftop PV generation potential is 2832.23 GWh, with significant economic returns.

Modeling and estimation of the optimal tilt angle, maximum incident solar radiation, and global radiation index of the photovoltaic system

This research was designed to apply measured and theoretically derived models to estimate the optimal tilt angle (β), maximum incident solar radiation (HT), and global radiation index (GRI) in Lagos and 37 metropolitan cities in Nigeria. Six modules were mounted at different tilt angles with two modules north-facing, three south-facing, and one positioned horizontally to determine the orientation and tilt angle performance. Overall, the 16.8° module 4 south-facing tilted emerged as the best performing module for HT, with maximum output power, and much more than 6.174 annual earned energy reported on module 6 mounted horizontally. The GRI obtained from the six solar modules revealed a significant coefficient of 1.0269 for module 1 north-facing, 0.9923 for module 2 north-facing, 1.0217 for module 3 south-facing, 0.9609 for module 4 south-facing, and 1.0232 for module 5 south-facing for the values obtained from the horizontally positioned module 6. In-depth statistical analysis of the effectiveness of values observed against the predicted values to estimate the optimal and maximum inclination angle of incident solar radiation using error metrics and GPI revealed that model 5, model 12, model 14, model 17, and model 14 outperform the other estimation models in their respective categories. A similar statistical analysis of model 14 with the best performance was performed to estimate the best inclination angle in 37 metropolitan cities in Nigeria compared to two models consolidated in the literature; model 14 performed admirably in terms of accuracy compared to the two models obtained from the literature.

Numerical investigation on melting behaviour of phase change materials/metal foam composites under hypergravity conditions

The integration of electronic devices in aerospace vehicles leads to a significant increase in the heat dissipation, which makes thermal management a severe challenge. Due to the high thermal energy storage capacity and the excellent thermal diffusivity, phase change materials (PCM)/metal foam composite is a potential thermal management material. In order to deepen the understanding of melting behaviour of PCM/metal foam under hypergravity, the numerical model considering natural convection, flow resistance of metal foam, and non-equilibrium heat transfer is proposed, and the effects of inclination angle, hypergravity value, metal foam porosity, and pore density on the melting are analyzed. It shows that the inclination angle has a great influence on the morphology of the melting interface, while has limited influence on the variation of PCM liquid fraction. As the inclination angle changes from 0° to 180°, the heated wall temperature first decreases, and then increases after reaching the lowest value at 45°, which is the optimal inclination angle. With the rise of hypergravity value, natural convection is enhanced, the heated wall temperature is reduced, while the hypergravity value has limited effect on the PCM liquid fraction. Furthermore, with the increase of metal foam porosity, natural convection is enhanced, while the heated wall temperature and the melting time become larger. When the porosity is larger than 0.95, the effect of metal foam on natural convection suppression is greater than that of heat conductivity enhancement, leading to that the performance of PCM/metal foam is worse than that of the pure PCM. Besides, with the decrease of pore density, natural convection is enhanced, the heated wall temperature becomes lower. Therefore, metal foam with lower pore density is preferred. This paper provides guidance to the optimal design of PCM-based heat sink for aerospace applications.

Stability of expansive soil slopes reinforced with anchor cables based on rotational-translational mechanisms

Expansive soil slopes are usually characterized with conspicuous fissures. Pre-stressed anchor cables are effective techniques in improving the slope stability. Explicit considerations of the fissures and the suction effect become crucial in producing more realistic solutions. Based on the kinematic limit analysis theorem, this paper performs a limit analysis of the stability for expansive soil slopes stabilized by anchor cables. The upper bound solution to the slope stability was optimized and compared with the published solutions, demonstrating the applicability of the proposed method. An illustrative slope reinforced with two different reinforcement patterns was investigated to show the role of soil suction and anchor reinforcement in the safety assessments of expansive soil slopes. The results indicate that the slope stability and anchor reinforcement relate closely to the fissures. A threshold value of the fissure height exists, beyond which the slope stability is significantly reduced. An optimum inclination angle (ξopt) of anchors exists universally and is reduced as the anchor height, the internal friction angle and the surcharge load increase.

Theoretical and Simulation Prediction of Optimum Cover Inclination To Prevent Fall-Off Condensed Water Droplets

This study presented theoretical and simulation predictions to find the optimum glass cover inclination angle that can allow the water droplet underneath the surface to slide along it without fall-off. As a case study, the solar still main component that plays a big role on it is performance is the transparent glass cover that permits solar rays to pass through it and is used as a condensation surface for water vapor. The inclination angle of the cover is a very important parameter that provides confined space to increase the condensation process by fast cooling of the surface and result in more freshwater productivity. The theoretical prediction is obtained by modeling a set of mathematical equations that contain the main parameters necessary to slide the droplet along the surface without detaching it and solving them by using the MATLAB computer program. The simulation technique for the volume of fluid method uses the volume fraction equation with the level set applied in ANSYS Fluent software. The 3D model was created, and a water droplet was applied with adhesion force on the glass. It was found that the size of the droplet represented by its critical radius is a function of inclination angle. Also, it is found that for the angles larger than 15o , water droplets slide over the surface without separation. The optimum cover inclination provides both smooth slidings of droplets along with it and a suitable confined area that increases the rate of evaporation and condensation.

Simulation of a Low Concentrator Photovoltaic System Using COMSOL

The use of photovoltaic (PV) systems presents a great solution to high energy demand. Many factors limit the output of PV systems. One method of increasing the output of PV systems is to employ concentrators. The function of these concentrators is to increase the amount of solar radiation falling on a PV panel using optical devices. In this work, a simulation of a low concentrated photovoltaic system (LCPV) (V-trough model) will be conducted using COMSOL Multiphysics software package. The ray-tracing technique, based on the finite-element method, was used to study the performance of a V-trough without the incorporation of a tracking system. By investigating the effect of the mirrors’ inclination angles on the performance of the system, the optimum inclination angles were determined. The simulation was done for a non-tilted concentrator photovoltaic (CPV) system if placed in different geographical locations in Saudi Arabia with the inclination of the mirrors being changed every hour of the daylight. It was found that the concentration ratio of the suggested model increased for the city of Jeddah, for example, by 171% and 131% for double and partial coverage cases, respectively. In order to reduce the operation cost, the simulation was repeated with the restriction of the mirrors’ inclination to only three positions during the day. The concentration ratio decreased in this case by not more than 14%. When mirrors were fixed throughout the day, the concentration ratio dropped to about 50%. Such simulations will assist in investigating different designs of PV systems prior to their manufacturing. In addition, it could assist in determining the best geographic location for such CPV systems.

Three-dimensional steady state numerical analysis of inclined two phase closed thermosyphon for solar applications

A three-dimensional steady state CFD model was developed in ANSYS-Fluent CFD solver to analyze heat transfer capability as well as the wall temperature distribution along the lateral walls of thermosyphon. The physical properties of the fluid and other formulations were taken from the literature to perform the analysis. The CFD simulation predicted the temperature and pressure profile of liquid vapor mixture as well as the distribution of temperature over an entire wall of the thermosyphon for various operating conditions like heat transfer rates and inclination angles. The model was also validated with available experimental results.The CFD simulation helped to visualize the steady state wall temperatures over the entire wall of the two-phase closed thermosyphon (TPCT) the first time which is very difficult to find out by experiments. The influence of inclination angle on the wall temperatures distribution of the lateral surface of the thermosyphon was also analyzed. An optimum inclination angle for heat flux and filling ratio was determined by comparing thermal resistances values.

An approach to the design of photovoltaic noise barriers and a case study from Istanbul, Turkey.

Solar energy solutions that do not require additional space are critical. Noise barriers, which are built in low-value lands next to noise sources, provide effective areas for PV modules. There are many studies on using noise barriers as a sub-structure for photovoltaic systems, providing electricity generation besides noise reduction targets. Photovoltaic noise barrier (PVNB) technology combines noise control measures with renewable energy generation. In this study, it is aimed to develop an integrated design method that embeds solar energy technology in noise protection structures. The method is exemplified in an existing settlement located on the side of the road with heavy traffic. According to local climate and solar data, optimum tilt angles have been determined for annual, semi-annual, seasonal, and monthly periods. Noise barrier alternatives are derived with combinations of different diffraction edge sizes of barrier top and determined optimum inclination angles. The performance of the criteria that affect the PVNB effectiveness for alternatives was calculated through software tools. The energy generation potential of PVNB and its shading in adjacent blocks were calculated with PVsyst 6.7.7. The noise control efficiency of the structure was computed via SoundPLAN 7.2. TOPSIS method, one of the most common multi-criteria decision-making (MCDM) techniques, was used in the evaluation. As a result of TOPSIS, the best PVNB solution in the case study is the alternative that has 3-m and 2-m-wide edges and 58° and 31° tilted edges. In comparison with the current situation, the selected alternative will decrease 44% of the number of receiving points affected by noise and provide 524,804 kWh annual electricity generation.

Effect of multi-angle parameter on fluid flow characteristics of swirl-type oxygen lance

The supersonic jet characteristics of the oxygen lance nozzle play an important role in converter melting. In this study, the jet characteristics of swirl-type oxygen lance were investigated by numerical simulation. The velocity field, jet coalescence behavior and jet impact cavity area of swirl-type oxygen lance with different inclination and swirl angles were analyzed. The results demonstrate that compared with the traditional oxygen lance, the swirl angle accelerates the attenuation of the jet. However, the tangential velocity of jet is conducive to the rapid melting of the slag in the steelmaking process. With the increase of swirl angle and inclination angle, the velocity of jet decreases, the temperature of jet increases and the independence between jets is improved. With the increase of the swirl angle, the tangential velocity of the swirl-type oxygen lance increases, but the possibility of slag adhering to the nozzle surface increases. The effective impact area varies non-monotonically with the swirl angle. The optimum inclination and swirl angle of the swirl-type oxygen lance for a 260 t converter are 15° and 10° respectively. When the oxygen flow rate increases, the decay of jet velocity decreases and the effective impact area increases.