Nozzle System Research Articles

Fault detection of industrial large-scale gas turbine for fuel distribution characteristics in start-up procedure using artificial neural network method

In this study, artificial neural network (ANN) based on operating data is adjusted to detect fault operation of large-scale industrial gas turbine. To detect faults, the operating characteristics of gas turbine are first predicted for fuel injection characteristics because, in general, lots of the operating failures are occurred in start-up procedure when fuel distribution characteristics are frequently changed. Data from the GE 7FA gas turbine were used, and the fuel distribution and other operating parameters are set by input and output parameters, respectively, to analysis effect of fuel distribution. The start-up procedure is divided with eight operating process (OP) to detect fault operation by fuel distribution characteristics. An overheating start is detected when turbine exhaust temperature (TET) reaches 110%–120% of the design value with the conventional detecting method; by contrast, the proposed method can detect this problem in advance before OP4. Further, sensitivity analysis of gas turbine operating characteristic parameters for each nozzle was performed to detect not only operation failures but also problems in the fuel supply system. Fault detectability was different with each OP and nozzle, and nozzle system abnormalities can be detected in advance by the results of sensitivity analysis.

Increase of the efficiency in hot gas welding by optimization of the gas flow

The standard hot gas welding process uses a nozzle system consisting of multiple round tubes. With the top nozzle system, the weld seam is encapsulated to minimize heat loss and allow better control of the hot gas flow. This significantly reduces the required heating time of the polymer. Temperature measurements and welding tests with plates of various thicknesses and burst pressure specimens are performed to verify the improvements of the top nozzle. For polyamides with different base polymers and different glass fiber contents, an average reduction in heating time of up to 50 % is possible on average. The achieved weld strengths or burst pressures for the tested materials are comparable or higher with the top nozzle system. The top nozzle makes the process more economical due to a short cycle time and lower gas consumption. It can be added to existing hot gas tools. In addition, a larger process window, shorter heating time and higher achievable temperatures with the top nozzle lead to a higher acceptance of hot gas welding in industries. New weld able materials in turn open up new application areas and markets.

Nozzle Condition Monitoring System Using Root Mean Square of Acoustic Emissions during Abrasive Waterjet Machining

Machining of difficult-to-cut materials such as titanium alloys, stainless steel, Inconel, ceramic, glass, and carbon fiber-reinforced plastics used in the aerospace, automobile, and medical industries is being actively researched. One non-traditional machining method involves the use of an abrasive waterjet, in which ultra-high-pressure water and abrasive particles are mixed and then ejected through a nozzle, and the thin jet stream cuts materials. The nozzle greatly affects the machining quality, as does the cutting tool of general machining, so it is very important to monitor the nozzle condition. If the nozzle is damaged or worn, or if the bore size increases or the bore becomes clogged with abrasive, the material may not be cut, or the surface quality of the cut may deteriorate. Here, we develop a nozzle monitoring system employing an acoustic emission sensor that detects the nozzle condition in real time.

The dosimetric enhancement of GRID profiles using an external collimator in pencil beam scanning proton therapy.

The radiobiological benefits afforded by spatially fractionated (GRID) radiation therapy pairs well with the dosimetric advantages of proton therapy. Inspired by the emergence of energy-layer specific collimators in pencil beam scanning (PBS), this work investigates how the spot spacing and collimation can be optimized to maximize the therapeutic gains of a GRID treatment while demonstrating the integration of a dynamic collimation system (DCS) within a commercial beamline to deliver GRID treatments and experimentally benchmark Monte Carlo calculation methods. GRID profiles were experimentally benchmarked using a clinical DCS prototype that was mounted to the nozzle of the IBA-dedicated nozzle system. Integral depth dose (IDD) curves and lateral profiles were measured for uncollimated and GRID-collimated beamlets. A library of collimated GRID dose distributions were simulated by placing beamlets within a specified uniform grid and weighting the beamlets to achieve a volume-averaged tumor cell survival equivalent to an open field delivery. The healthy tissue sparing afforded by the GRID distribution was then estimated across a range of spot spacings and collimation widths, which were later optimized based on the radiosensitivity of the tumor cell line and the nominal spot size of the PBS system. This was accomplished by using validated models of the IBA universal and dedicated nozzles. Excellent agreement was observed between the measured and simulated profiles. The IDDs matched above 98.7% when analyzed using a 1%/1-mm gamma criterion with some minor deviation observed near the Bragg peak for higher beamlet energies. Lateral profile distributions predicted using Monte Carlo methods agreed well with the measured profiles; a gamma passing rate of 95% or higher was observed for all in-depth profiles examined using a 3%/2-mm criteria. Additional collimation was shown to improve PBS GRID treatments by sharpening the lateral penumbra of the beamlets but creates a trade-off between enhancing the valley-to-peak ratio of the GRID delivery and the dose-volume effect. The optimal collimation width and spot spacing changed as a function of the tumor cell radiosensitivity, dose, and spot size. In general, a spot spacing below 2.0 cm with a collimation less than 1.0 cm provided a superior dose distribution among the specific cases studied. The ability to customize a GRID dose distribution using different collimation sizes and spot spacings is a useful advantage, especially to maximize the overall therapeutic benefit. In this regard, the capabilities of the DCS, and perhaps alternative dynamic collimators, can be used to enhance GRID treatments. Physical dose models calculated using Monte Carlo methods were experimentally benchmarked in water and were found to accurately predict the respective dose distributions of uncollimated and DCS-collimated GRIDprofiles.

Survey on Artificial Intelligence Based Autonomous Inspection Systems for an Industry 4.0

The main idea of this project is to inspect the manufactured component through machine vision system .Through this project mainly the dimension correctness of the manufactured component is tested .The aim of the project is to improve the quality of the product .The various parts of the automatic inspection machine includes conveyors ,test table ,inspection camera, rejection bin ,image processing unit, monitoring system .Firstly, the specimen to be inspected is taken to the rotating test table by means of a conveyors .Then the inspection camera‟s detect the specimen under study on the rotating test table and the image of the specimen is captured by the camera and taken for further processing .The image is processed in terms of pixels by the image processing system. The generated image of the specimen is compared with the standard specimen by the image processing system and the result of inspection is projected on the monitoring system. The rejected specimen is automatically taken to the rejection bin by means of nozzle systems. This process is again repeated for every specimen. The overall setup of the machine is bridge type so it could be possible to inspect more than one work piece at a time.

Thermal Qualification of the UHTCMCs Produced Using RF-CVI Technique with VMK Facility at DLR

Ultra high-temperature ceramic matrix composites (UHTCMCs) based on carbon fibre (Cf) have been shown to offer excellent temperature stability exceeding 2000 °C in highly corrosive environments, which are prime requirements for various aerospace applications. In C3Harme, a recent European Union-funded Horizon 2020 project, an experimental campaign has been carried out to assess and screen a range of UHTCMC materials for near-zero ablation rocket nozzle and thermal protection systems. Samples with ZrB2-impregnated pyrolytic carbon matrices and 2.5D woven continuous carbon fibre preforms, produced by slurry impregnation and radio frequency aided chemical vapour infiltration (RF-CVI), were tested using the vertical free jet facility at DLR, Cologne using solid propellants. When compared to standard CVI, RFCVI accelerates pyrolytic carbon densification, resulting in a much shorter manufacturing time. The samples survived the initial thermal shock and subsequent surface temperatures of >2000 °C with a minimal ablation rate. Post-test characterisation revealed a correlation between surface temperature and an accelerated catalytic activity, which lead to an understanding of the crucial role of preserving the bulk of the sample.

Optical Sensor System for Chemical Flow Rate Monitoring with Direct Nozzle Injection

HighlightsA novel optical sensor system was developed to accurately measure simulated chemical (water with dye) flow rates observed with direct nozzle injection systems for agricultural sprayers.The average error in chemical flow rate estimates was only 2% across a typical range of injection rates.The prototype optical sensor system was capable of detecting dye dilutions to a level of 1:150,000.Abstract. Direct injection systems have the potential to provide several benefits to spray applicators (e.g., easing boom cleanout procedures); however, lag time and proper mixing continue to hinder adoption. Development efforts have typically focused on moving the chemical injection point closer to the nozzle to improve the application rate response. This poses an important challenge for proper metering of the chemical, i.e., accurate measurement of extremely low chemical flow rates. In this study, an optical sensor system was integrated with a typical carrier flowmeter and calibration methodology to measure chemical flow rates for a direct nozzle injection sprayer. The optical sensor used a light-emitting diode (LED) and photodiode pair to measure the absorbance of a dye mixed with a simulated chemical solution. Laboratory tests were conducted to evaluate the measurement accuracy of the system in which sensor output was compared directly to measurements from a spectrophotometer. Results indicated that the calibrated sensor system was able to estimate the simulated chemical flow rate with an average error of 2%. The sensor system was also capable of accurate measurements as the initial concentrations of dye mixed with the chemical solution varied. Keywords: Application equipment, Pesticides, Sprayers, Spraying equipment.

Analysis of two different nozzle systems for hot gas welding using CFD simulations and meas-urement results

Analysis of two different nozzle systems for hot gas welding using CFD simulations and meas-urement results

Beeinflussung der Faserorientierung von Polypropylen und Polyamid im Spritzgießprozess durch einen drehenden Werkzeugkern

Beeinflussung der Faserorientierung von Polypropylen und Polyamid im Spritzgießprozess durch einen drehenden Werkzeugkern

Production and Characterization of Commercial Aluminum Powders by a New Nozzle Design and Atomization Unit

Abstract: A large area cross section of the production of spherical metal powders by gas atomization in the manufacturing method. Powder metal characteristic improves with small powder size. This aim was realized by vertical gas atomization unit, a new a closely-matched nozzle system and manufacture. In the experimental studies, pure aluminium powders which has an important place in the automotive, air and defence industries were produced. In the studies carried out with the Vertical Gas Atomization unit, aluminium was superheated up to 900°C and atomized at different gas pressures (20-30 bar). Scanning electron microscope (SEM) and particle size measuring device were used for the characterization and size measurements of the produced powders, respectively. The average particle size of the finest powder produced with increasing atomization pressure was determined as d50=19.50µm. Aluminium powder shape and morphology was used as spherical and very little satellization was seen. Keywords: Powder Metallurgy, Atomisation, Nozzle, Al powder, Characterisation

Frontally polymerizable shape memory polymer for 3D printing of free-standing structures

Four-dimensional (4D) printing is used to describe three-dimensional (3D)-printed objects with properties that change over time. Shape memory polymers (SMPs) are representative materials for 4D printing technologies. The ability to print geometrically complex, free-standing forms with SMPs is crucial for successful 4D printing. In this study, an SMP capable of frontal polymerization featuring exothermic self-propagation was synthesized by adding cyclooctene to a poly(dicyclopentadiene) network, resulting in switching segments. The rheological properties of this SMP were controlled by adjusting incubation time. A nozzle system was designed such that the SMP could be printed with simultaneous polymerization to yield a free-standing structure. The printing speed was set to 3 cm min−1 according to the frontal polymerization speed. A free-standing, hexagonal spiral was successfully printed and printed spiral structure showed excellent shape memory performance with a fixity ratio of about 98% and a recovery ratio of 100%, thereby demonstrating the 3D printability and shape memory performance of frontally polymerizable SMPs.

Influence of the filling gas mixture on the interruption capability of medium voltage load break switches

In today’s medium voltage switchgear SF6 is commonly used as insulating and arc quenching medium. Because of its high potential impact on the environment a substitution with an environmentally friendly alternative is pursued. In this paper the influence of the mixing ratio of carbon dioxide nitrogen mixtures as filling gas on the interruption capability in medium voltage load break switches is investigated. The interruption capability is regarded by means of the thermal interruption performance as well as the dielectric recovery of a model load break switch. The model load break switch allows an axial arc blowing with variable pressure and uses an exchangeable nozzle system.

Investigation of inter-zonal heat transfer in large space buildings based on similarity: Comparison of two stratified air-conditioning systems

Stratified air-conditioning (STRAC) has been deployed in large space buildings to achieve vertical thermal stratification with significant energy-saving potential. This research focuses on two typical STRAC systems: floor-level sidewall air-supply system (FSAS) and nozzle sidewall air-supply system (NSAS). By employing experiment and CFD methods, airflow pattern and heat transfer between the unoccupied and occupied zone under the two air supply systems are investigated in a reduced-scale laboratory. The geometric models of the prototype building, with a geometrical scaling factor of 4:1, are established according to similarity principles and studied by CFD simulation. The results demonstrate that the two scales have similar indoor thermal performances. The numerical simulation results of the prototype building provide and compare commonly used inter-zonal heat transfer coefficients of actual large space buildings with the two typical STRAC systems. For FSAS, heat conduction caused by temperature gradient dominates the inter-zonal heat transfer. In NSAS, both heat conduction due to temperature gradient and heat convection due to airflow contributes equally to this heat transfer. The inter-zonal heat transfer coefficient Cb is affected by the airflow pattern and zonal division, and closely associated with local turbulence intensity.

Rotating co-flow jets with horizontal lip and shape transition

Purpose Control over large-scale coherent structures and stream-wise vortices lead to enhanced entrainment/conservation of the jet which is desirable for most free jet applications such as design of combustion chamber in jet engines and flame length elongation of welding torch used for metal cutting. Design/methodology/approach A co-flow nozzle with lip thickness of 2 mm, between the primary (inner) and secondary (outer) flow, is selected. Three nozzle combinations are used, i.e. C–C (circle–circle), C–E (circle–ellipse) and C–S (circle–square) for acquiring comparative data. For these nozzle combinations, inner nozzle exit plane is kept as a circle, whereas the outer nozzle exit planes are varied to circle, ellipse and square. The exit plane area of outer nozzle for the nozzle combinations has equivalent diameter, De. The nozzles are fabricated in a way that the outer nozzle can be rotated along the longitudinal axis, keeping the inner nozzle intact. Findings The C–C nozzle combination is effective in low Mach number regime in decaying the jet, when the rotational component is introduced. Around 30% reduction in the jet core length is observed for the C–C nozzle combinations without any lip. The C–E nozzle shows sedative result in decaying or preserving the jet. The C–S nozzle combination shows interesting phenomenon, whereby the low subsonic case tends to conserve the jet by 15% and the higher subsonic case tends to decay the jet by 10%. Originality/value The developed nozzle systems show both conservative and destructive effect on the jet, which is desirable for the mentioned applications.

Study of Different Developments of Artificial Intelligence Based Inspection Machine

The purpose of this paper is to describe the survey of the inspection systems and the manufactured component through machine vision system. With this project, mainly the dimension correctness of the manufactured component is tested. The very main goal is to improve the quality of the product. Among the various components of the automatic inspection machine are conveyors, test tables, inspection cameras, reject bins, image processing units, and a monitoring system. Initially, the specimen to be inspected is conveyed by means of conveyors. The inspection camera detects the specimen and takes an image of it for further processing. The image is then processed by the image processing system in terms of pixels. Through the image processing system, the generated image of the specimen is compared with the standard specimen, and the inspection result is projected on the monitor system. The rejected specimen is automatically directed to the rejection bin through nozzle systems. The process is repeated for each specimen. The setup of the machine is bridgetype, so it is possible to inspect more than one piece at a time.

Characterization of PI/PVDF-TrFE Composite Nanofiber-Based Triboelectric Nanogenerators Depending on the Type of the Electrospinning System.

An electrospun nanofiber membrane significantly improves the electrical performances of triboelectric nanogenerators (TENGs) due to its high surface area. In recent years, composite nanofibers were applied to a TENG using various electrospinning system types to further enhance the performance of TENGs; however, the effects of the systems on the energy harvesting capability of TENGs have not been investigated thoroughly. This study aims to fabricate polyimide/poly(vinylidene fluoride-co-trifluoroethylene) composite nanofiber-based TENGs with three different nozzle systems: single nozzle, conjugated nozzle, and multinozzles, and two different collectors: plate collector and drum collector. A TENG with multinozzle-drum system-based nanofibers produced an output voltage of 364 V, a short-circuit current of 17.2 μA, a transferred charge of 29.72 nC, and a power density of 2.56 W/m2 at a load resistance of 100 MΩ, which were ∼7 times higher than those of other system-based nanofibers. Under the 10,000 cycles of loading, the TENG stably harvested electric energy. The TENG could also harvest energy from the human body motions, and it is sufficient to illuminate 117 light-emitting diodes and drive several electronic devices. The proposed TENG exhibits excellent electric performances as a wearable energy harvester.

Multiparameter Optimization of Thrust Vector Control with Transverse Injection of a Supersonic Underexpanded Gas Jet into a Convergent Divergent Nozzle

The optimal design of the thrust vector control system of solid rocket motors (SRMs) is discussed. The injection of a supersonic underexpanded gas jet into the diverging part of the rocket engine nozzle is considered, and multiparameter optimization of the geometric shape of the injection nozzle and the parameters of jet injection into a supersonic flow is developed. The turbulent flow of viscous compressible gas in the main nozzle and injection system is simulated with the Reynolds-averaged Navier–Stokes (RANS) equations and shear stress transport (SST) turbulence model. An optimization procedure with the automatic generation of a block-structured mesh and conjugate gradient method is applied to find the optimal parameters of the problem of interest. Optimization parameters include the pressure ratio of the injected jet, the angle of inclination of the injection nozzle to the axis of the main nozzle, the distance of the injection nozzle from the throat of the main nozzle and the shape of the outlet section of the injection nozzle. The location of injection nozzle varies from 0.1 to 0.9 with respect to the length of the supersonic part of the nozzle; the angle of injection varies from 30 to 160 degrees; and the shape of the outlet section of the injection nozzle is an ellipse with an aspect ratio that varies from 0.1 to 1. The computed fluid flow in the combustion chamber is compared with experimental and computational results. The dependence of the thrust as a function of the injection parameters is obtained, and conclusions are made about the effects of the input parameters of the problem on the thrust coefficient.

Design and fabrication of multi utility unmanned robot

Humans have dreamed of mechanical devices to ease their chores and assist them in performing repetitive tasks for thousands of years. This project can be identified as a key tool for reducing the vulnerability of human lives when we deal with emergencies. The human presence is very much important in dealing with all emergencies. Even if it is a fire accident, disinfection activities or surveillance in places where the accessibility is very much limited. Each case the first responders’ lives are at risk. Their direct contact in the impact zones can put them in danger. This is where unmanned robots can be utilized. In this paper a multi utility unmanned robot equipped with a long range control system, nozzle system, camera for surveillance, and an all-terrain track to conquer different working environments was designed and fabricated. Thus the threat for first responder’s and health workers can be reduced.

Numerical Investigation of an Integrated Ejector Nozzle with the Nozzle Pressure Ratio of 2.97

The design of the integrated ejector nozzle system directly affects the secondary mass flow rate and the trust characteristics of the aero-engine. The numerical simulation was used to study the effects of longitudinal distance between engine nozzle exit and aircraft surface and radius of ejector nozzle exit on the performance of the integrated ejector nozzle system. Results indicates:(1) As NPRs increases, secondary mass flow rate and thrust coefficient of ejector nozzle system generally increase;(2) the effect of D2/D0 is not obvious but D3/D0 has great effect, and the value of D3/D0 designed between 1.1 and 1.25, which is beneficial to the secondary mass flow rate and thrust coefficient of ejector nozzle system;(3) the combination design of D2/D0 and D3/D0 can restrain the flow separation between the primary flow and have inhibitory effect on the over-expansion of low nozzle pressure rate.

On the Determination of the Chip Nozzle Recognition System by Using Machine Vision

To solve the problem of chip damage caused by the using the wrong type of vacuum nozzle during the packaging of semiconductor chips. A recognition system of vacuum nozzle based on machine vision was proposed. In this research, 29 kinds of lifting nozzles are selected as test samples. The backlight intensity of two lifting nozzle images (one strong and one weak separately) is collected at the first beginning. Then, the Blob analysis method is using to analyze the weak backlighting image. The area of the lifting nozzle and the minimum outer rectangular feature can be obtained subsequently. To identify the shape of the liftin nozzle (round or square), the area ratio is calculated. At the same time, the minimum outer rectangular of the lifting nozzle is selected as the reference rectangle. Then, construct the measurement rectangle. The 2-dimensional size of the lifting nozzle is measured as well. Meanwhile, for the strong backlight image, the average value of the grayscale which located within the minimum outer rectangle is calculated. Therefore, the color (black, white, or beige) of the nozzle can be identified. Finally, the sample data is saved to the database as the sample database. During the recognition process, the shape, color, and size of the lifting nozzle being analyzing are using as the parameter to realize the condition inquire. The experimental results show that the recognition accuracy of this method is 98.85%, and the recognition time of one nozzle is around 1 second, which meets the requirements of practical application.