Water-cooled Tube Research Articles

Plasma discharge experiments of a Faraday shieldless driver for high-power and long-pulse radio frequency ion source for NBI application.

Due to the high stability and less maintenance, the radio frequency (RF) driven ion source is preferred for the neutral beam injection (NBI) system. In a popular design of the RF ion source for NBI application, a Faraday shield (FS) is installed inside the RF plasma driver to protect the discharge tube. However, the FS also brings some drawbacks, such as lowering the RF power transfer and increasing the processing difficulty. A prototype of the RF plasma driver without FS and with mature manufacturing technology has been developed by using a water-cooled discharge tube. After basic testing, this prototype was further tested under the RF plasma discharge experiments in views of high power, long pulse, and long term. The reliability and its plasma characteristics were the focus of these experiments, also for the hidden issues. The results show that the prototype could generate stable and high-density plasma without any damage or sputtering mark. An RF plasma discharge of 50 kW and 20s has been achieved. The expected frequency tuning was equally effective on the prototype. Moreover, compared to the RF plasma driver with FS, the prototype could produce higher electron density in the extraction region under the same RF power. Of course, some of the shortcomings of the prototype have also been exposed in the experiments and will be improved in subsequent experiments.

Analysis of cracking failures in water-cooled wall fins and thermal peaking unit mitigation strategies

Abstract The causes of leakage in the submitted superheater tubes were analyzed using the analysis of macroscopic morphology, chemical composition, and metallography. The analysis results indicate that the chemical composition of the failed superheater tube is within the standard range, and the metallographic structure is ferrite + pearlite, with no abnormalities in the metallographic structure. The main reason for the failure of water-cooled wall tubes and superheater tubes may be the formation of fatigue cracks on the inner and outer walls of the superheater tubes under cyclic stress. As the two fatigue cracks grow and converge, penetrating cracks form, ultimately leading to the initial leakage of the superheater tubes. In addition, the excessive depth of the weld pool in the fins of the superheater tube is another crucial factor that promotes accelerated cracking of the superheater tube. It is recommended that power plants reasonably regulate the temperature difference fluctuation rate of boilers to prevent similar failure accidents from occurring.

Microstructure, Hardness and High-Temperature Corrosion Behaviors in Sulfur-Containing Environment of Laser Cladding Y2O3/IN625 Composite Coating.

Water-cooled wall tubes are susceptible to high-temperature corrosion during service. Applying high-performance coatings via laser cladding on the tube surfaces can significantly enhance corrosion resistance and extend the service life of the tubes, providing substantial economic advantages. This paper prepared Y2O3/IN625 composite coating by means of high-speed laser cladding. Furthermore, the effects of Y2O3 addition on the microstructure evolution, hardness, as well as the high-temperature corrosion behaviors have been systematically investigated. The results show that Y2O3 addition can effectively refine the microstructure of the Inconel 625 coating, but the phase composition has little change. The coating's hardness can also be improved by about 7.7%, reaching about 300 HV. Compared to Inconel 625 coating, the Y2O3-added composited coating shows superior high-temperature corrosion resistance, with the corrosion mass gain decreased by about 36.6%. The denser and tightly bonded Cr-rich oxides layer can be formed adjacent to the coating surface, which plays a predominant role in improving the coating corrosion resistance.

Realization of a gas puff imaging system on the Wendelstein 7-X stellarator.

A system for studying the spatiotemporal dynamics of fluctuations in the boundary of the W7-X plasma using the "Gas-Puff Imaging" (GPI) technique has been designed, constructed, installed, and operated. This GPI system addresses a number of challenges specific to long-pulse superconducting devices, such as W7-X, including the long distance between the plasma and the vacuum vessel wall, the long distance between the plasma and diagnostic ports, the range of last closed flux surface (LCFS) locations for different magnetic configurations in W7-X, and management of heat loads on the system's plasma-facing components. The system features a pair of "converging-diverging" nozzles for partially collimating the gas puffed locally ≈135mm radially outboard of the plasma boundary, a pop-up turning mirror for viewing the gas puff emission from the side (which also acts as a shutter for the re-entrant vacuum window), and a high-throughput optical system that collects visible emission resulting from the interaction between the puffed gas and the plasma and directs it along a water-cooled re-entrant tube directly onto the 8 × 16 pixel detector array of the fast camera. The DEGAS 2 neutral code was used to simulate the Hα (656nm) and HeI (587nm) line emission expected from well-characterized gas-puffs of H2 and He and excited within typical edge plasma profiles in W7-X, thereby predicting line brightnesses used to reduce the risks associated with system sensitivity and placement of the field of view. Operation of GPI on W7-X shows excellent signal-to-noise ratios (>100 at 2 Mframes/s) over the field of view for minimally perturbing gas puffs. The GPI system provides detailed measurements of the two-dimensional (radial and poloidal) dynamics of plasma fluctuations in the W7-X edge and scrape-off layer and in and around the magnetic islands outside the LCFS that make up the island divertor configuration employed on W7-X.

БАГАТОШАРОВІ ІНДУКТОРИ ДЛЯ УСТАНОВКИ ІНДУКЦІЙНОЇ ТЕРМООБРОБКИ АЛЮМІНІЄВИХ ЗЛИВКІВ ПРИ ПРЕСУВАННІ КАТАНКИ ДЛЯ СИЛОВИХ КАБЕЛІВ

On the basis of the developed mathematical model, computer (numerical) modeling of electrothermal processes in a multi-layer inductor installation, which is used for heating cylindrical aluminum ingots (blanks) before pressing the wire rod, as a basis for obtaining current-conducting cores of power cables from it, was carried out. Single-phase and three-phase multilayer inductors of the galette type were studied, as a result of which it was shown that the maximum value of the electrical efficiency of such an installation for both inductors is provided by their three-layer winding with a water-cooled copper tube of rectangular section. For both inductors, distributions along the radius and length of the aluminum blanks of the volumetric specific power and the specific linear power of heat release from the eddy currents induced in the blanks were obtained. For a three-phase inductor, such distributions were obtained when feeding it with voltages with phase shift angles of 120 and 60 degrees. The losses in the turns of the inductors and their distribution along the length and layers of both inductors were also studied. Ref. 8, fig. 7, tables 2.

Research and application of low-frequency eddy current detection technology for heating surface tube of power plant boiler

Abstract In this paper, an ultra-low frequency magnetic detection method for the shedding of oxide layer on the inner wall of austenitic stainless steel heating surface tubes in power plant boilers and a far-field eddy current automatic detection method for water-cooled wall tubes are introduced. The probe selection, comparison sample making, detection voltage, detection current, signal phase and amplitude of ultra-low frequency magnetic detection, and far-field eddy current automatic detection methods are tested and studied, which provide reference detection parameters for practical detection applications. According to on-site practical application verification, this detection method can quickly, intuitively, and accurately detect the oxide layer peeling off the inner wall of austenitic stainless steel pipes and the defects on the inner and outer walls of water-cooled wall pipes, providing a feasible and effective means for the quality supervision and safe operation of the power plant boilers.

Comparison of two vacuum system technologies for the synchrotron storage ring: case study of Iranian Light Source Facility

The current study compares two vacuum system designs for the Iranian Light Source Facility (ILSF) storage ring: conventional vacuum system design with stainless-steel vacuum chambers that are pumped by Non-Evaporable Getter (NEG) cartridges and ion pumps. In this design, all synchrotron radiation is absorbed by the local photon absorbers. In the second design, the water-cooled copper tubes that are coated with NEG materials are used as the vacuum chambers. This study will illustrate the advantages of using the NEG-coated vacuum chambers over the conventional design with the stainless-steel chambers. Since the two designs for ILSF are now completed, some of the details of this comparison might be interesting to other light sources, especially those that have plans to upgrade to a 4th generation.

Engineering design and manufacturing of a radio frequency plasma driver without Faraday shield for NBI application

A radio frequency (RF) driven ion source is favorable for high-power and long-pulse neutral beam injection (NBI) system. To reduce the damage caused by the isotropic heat and particle fluxes from the plasma, the traditional RF plasma driver of the NBI ion source introduces a Faraday shield (FS) for protection. However, the simulations and experiments show that the FS seriously affects the RF coupling and around 50 % of the input power deposits on the FS. The water-cooled discharge tubes with a double-layer ceramic structure have been developed to avoid using the FS structure. It's expected to improve the RF power transfer efficiency and to promote the development of high-power and long-pulse RF ion source. To verify the feasibility of the double-layer ceramic structure, the paper has carried out the fluid-thermal-structural coupling analysis and the fracture mechanical analysis on two proposed types: the alumina ceramic brazing structure and the silicon nitride ceramic bonding structure. The sample tests and the prototype manufacturing have been completed. Preliminary tests of the plasma discharge on the prototype of the alumina ceramic brazing structure have been launched. A plasma discharge of 30 kW and 20 s have been achieved.

Leakage of water-cooled wall tube in subcritical boiler

Usually, heating surfaces used in thermal power plant boilers include economizers, water-cooled walls, superheaters, and reheaters, abbreviated as the “four tubes” of boilers. The leakage of the heating surface is a common form of unplanned shutdown in thermal power plants, accounting for more than 50% of abnormal shutdown accidents of units. Once the heating surface explosion occurs, the thermal power plant needs to shut down for treatment, resulting in huge losses in power generation and fuel consumption during startup and shutdown. This has a huge impact on the safety production and economic benefits of the enterprise. In this paper, the leaked water-cooled wall tube in the subcritical boiler was studied by means of microstructure analysis, hardness test, energy spectrum analysis, chemical composition test, macro-morphology inspection, and tensile test. The results revealed that the oxygen concentration difference between the area installed in ceiling pouring material and the area exposed to the air can result in significant differences in electrode potential between different areas of the front water wall tube passing through the ceiling. An oxygen concentration difference battery is formed. In this way, the water-cooled wall steel pipe continuously corroded and thinned. Finally, perforation leakage occurred under the pressure of the internal high-temperature medium.

SIMULATION ANALYSIS OF SHELL AND TUBE HEAT EXCHANGER USING DIFFERENT FLUIDS

There are many models to characterize the behavior of the heat exchangers encountered in many industries. There are several correlations available, so that the heat transferred and the thermal stresses can be evaluated. Shell and Tube heat exchangers are having special importance in boilers, oil coolers, condensers, and pre -heaters. They are also widely used in process applications as well as the refrigeration and air conditioning industry. The robustness and medium weighted shape of Shell and Tube heat exchangers make them well suited for high pressure operations. The present work deals with the design and analysis of water-cooled shell and tube condenser and we have shown how to done the thermal analysis by using theoretical formula, for this we have chosen an industrial problem of 8 ton capacity of counter flow shell and tube heat exchanger of water type. The condenser is designed using theoretical procedures. The condenser is modeled by using the dimensions obtained from the design procedures. Then thermal analysis is carried out in SOLIDWORK flow simulation. The results obtained through the analysis are discussed in detail and compared with analytic values. .Key Words: Heat exchanger, Perforated rings, Reynolds number, Overall heat transfer coefficient.

Characterization of Magnetic Susceptor Heating Rate Due to Hysteresis Losses in Thermoplastic Welding

Welding techniques are emerging as a new method to join thermoplastic composite parts. They present a fast and efficient alternative to adhesives and mechanical fasteners. Induction welding is a welding technique that relies on the application of an oscillating magnetic field on the joining interface, where a material called a magnetic susceptor generates heat by interacting with the applied magnetic field. In this work, susceptors relying on magnetic hysteresis losses made of polyetherimide (PEI) and nickel (Ni) particles are investigated with varying Ni concentration. The materials are mixed using an internal mixer and pressed to form films approximately 500μm thick. To characterize the heating rates of the susceptor materials, samples are placed on an induction coil – a water-cooled copper tube in which AC current (frequency 388kHz), generates an alternating magnetic field – and the temperature evolution is measured using a thermal camera. An increasing concentration of Ni particles results in increased heating rate and maximum temperature reached by the samples. The temperature-time experimental curves are compared with theoretical heating curves to verify if the model can be used to predict the temperature evolution at the joining interface during a welding process.

УДОСКОНАЛЕННЯ КОНСТРУКЦІЇ ВОДООХОЛОДЖУВАНИХ ПАНЕЛЕЙ ДУГОВИХ СТАЛЕПЛАВИЛЬНИХ ПЕЧЕЙ ЛИВАРНОГО КЛАСУ

The article outlines the importance of the foundry industry and the role of arc steelmaking furnaces (ASFs) in it. It was noted that water-cooled panels in EAFs are key elements that ensure the structural integrity and safety of furnaces by removing excess heat during steelmaking. An analysis of literature sources has revealed that there are certain issues that characterize the imperfections of certain structural parts of modern water-cooled panels, such as insufficient cooling efficiency, corrosion, and leaks, which lead to a decrease in the performance of the BF and an increase in energy consumption. These factors have been analyzed and some optimization ways have been identified to improve overall efficiency and durability. The article emphasizes that modern technologies can reduce the consumption of energy and refractory materials by reducing the capacity of the steelmaking bath and optimizing the heat balance. Particular emphasis is placed on the potential for modernizing water-cooled panels to improve the efficiency of the steelmaking process. The paper reveals the mechanism of operation of water-cooled chipboard panels as a spatial system of steel tubes connected by means of transition elements and placed with different densities and a layer of thermal insulation material in the intertube space. This determined the need to improve the design of the panels by optimizing their spatial structure to ensure a more efficient heat transfer process. Improving the energy efficiency of chipboard means reducing heat energy losses, which, among other things, ensures more stable operation during melting, reduces component wear and extends the service life of water-cooled panels. The design of the water-cooled panels has been improved by varying the distance between the axes of the water-cooled tubes depending on their diameter and spatial location. This design makes it possible to optimize the layer of heat-insulating material and minimize unproductive heat loss. Failure to comply with the calculated value of the pipe spacing can lead to increased heat loss. The calculations and graphical dependencies demonstrate the efficiency of heat flow distribution and minimization of heat losses. The new design reduces heat loss by 45% and improves the performance of water-cooled panels.

Preliminary experiments of diagnostic system based on secondary electron emission for CRAFT NBI

Neutral beam injection is one of the main auxiliary heating methods in Tokamak nuclear fusion device. The calorimeter which will be applied in Neutral beam injection system at Comprehensive Research Facility for Fusion Technology (CRAFT) is design for beam cutoff measurement, but limited by the design of double-layer water-cooling copper tubes paralleled to each other, the diagnostic system based on thermocouples cannot give the horizontal beam profile. To satisfy the requirement of diagnostic system, a beam diagnostic system based on Secondary Electron Emission (SEE) is designed. In order to achieve this goal, the rules of secondary electron emission are analyzed based on finite element methods (FEM) and the primary experiment has been carried out. Firstly, the laws of secondary electron emission during the beam bombarding on the calorimeter are analyzed; secondly, a set of signal acquisition system is set up, including sampling and filtering; finally, a preliminary experiment is carried out and the relationships between the signal of secondary electrons and the parameters, such as beam energy, beam current and bias voltage, are obtained. These results lay a foundation for the subsequent construction of the beam diagnostic system for CRAFT neutral beam injector (NBI).

HF02-04 KEEPING IT REEL: PHOTOGRAPHY AND CINEMATOGRAPHY IN UROLOGY

You have accessJournal of UrologyCME1 Apr 2023HF02-04 KEEPING IT REEL: PHOTOGRAPHY AND CINEMATOGRAPHY IN UROLOGY Kit Yuen, Alexis Steinmetz, and Ronald Rabinowitz Kit YuenKit Yuen More articles by this author , Alexis SteinmetzAlexis Steinmetz More articles by this author , and Ronald RabinowitzRonald Rabinowitz More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003242.04AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The ability to photograph, film, and eventually record human pathology and surgical procedures has greatly influenced urologic training and practice. Given that urology routinely uses endoscopy and minimally invasive techniques, it is no surprise that the history of film is closely intertwined with the field. METHODS: A review of textbooks, manuscripts, online texts, was performed on the development and application of photography and cinematography in urology. RESULTS: The precursor to the first camera—camera obscura—was described in 2674 BCE in China. A decade before the first photographic camera was invented in 1816, German physician Phillip Bozzini developed the forerunner of the urologic endoscope, the Lichtleiter. It consisted of a silver funnel illuminated by candlelight reflecting off angled mirrors. In 1867, Julius Bruck developed the diaphanoscope, a water-cooled glass tube inserted into the rectum or vagina to transilluminate the bladder. Thomas Stein constructed the Photo-endoskop in 1874, capable of producing an instant negative picture; he captured photos of the urethral mucosa. Maximilian Nitze was intrigued by endovesical photography as cystoscopic findings were difficult to reproduce with drawings. He applied an internal light source to his cystoscope using an electrically-heated platinum wire behind a quartz shield and went on to present “Photography of the Human Urinary Bladder” at the Berlin Medical Society in 1894. Co-founder of the AUA History Forum, Wirt Dakin, filmed the first urologic movie in 1916—an open prostatectomy performed on the roof of the LA General County Hospital. He presented his work at the 1917 AUA meeting in Chicago. The first successful black and white film of the human bladder was presented at the 1929 German Cinema Society meeting. Inspired by a German WWII cystoscope with a Leica camera attachment and frustrated by the difficulty of photographing bladder tumors, urologist James Gow worked with Harold Hopkins to improve the cystoscope. Karl Storz had developed flexible fiberoptics to provide a light source without generating a significant amount of heat within the body; the rod-lens cystoscope that launched in 1967 in Munich combined their innovations and produced photographs of excellent quality. By the 1960s cameras were used to televise endoscopy images, and color film for video endoscopy became available in 1972. Urologic journals now include dedicated sections to photography and videography as means of advancing the field. CONCLUSIONS: In the past two centuries, film has rapidly advanced as a cornerstone of urologic training and practice. Source of Funding: NA © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e251 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Kit Yuen More articles by this author Alexis Steinmetz More articles by this author Ronald Rabinowitz More articles by this author Expand All Advertisement PDF downloadLoading ...

Influence of Foreign Body Blockage in Water Cooling Wall on Flow and Heat Transfer

The ultra (super) critical units, as mainstream thermal power units, often need to participate in deep peak shaving. The variable load and high frequency peak regulation will lead to the partial increase of the temperature of the water-cooled wall and the phenomenon of local over-temperature. Aiming at this situation, the numerical investigation on the water-cooled wall of the #5 boiler in She-yang-gang was performed. The results show that the welding nodules and the foreign bodies in the water-cooled tube have a significant effect on the wall temperature. Moreover, with the increase of the blocking ratio (β), the mass flow in the tube decreases significantly, and the mass flow in the adjacent tubes rising. Further the increase of the mass flow is noteworthy in the nearest tubes. When the β of the target tube is higher than 0.4 the possibility of exceeding the maximum temperature limit of water-cooled wall tube material increases. The deposition of foreign body on the inner wall of the tube weakens the convective heat transfer between the inner wall and the fluid, which makes the wall temperature rise faster than other places. The more serious the deposition, the more obvious this phenomenon is.

Frequency domain analysis of density wave oscillations for two-phase flow in a vertical tube

In order to investigate the boundary characteristics of density wave oscillations in nuclear reactor steam generators and boiler water-cooled wall tubes, a frequency domain method numerical calculation model applicable to different geometrical structures and operating parameters was developed. In order to make the results of the model more accurate, the state of the fluid at the outlet of the heated pipe and the time delay were fully considered on the basis of the traditional model. Depending on the physical properties of the fluid at the outlet of the heated pipe, the model calculation area was divided into single-phase, two-phase and superheated zones. Small-perturbation linearization and Laplace transform were performed on the conservation equations in the three regions. The Nyquist stability criterion was used in matlab software to judge the stability of the flow, and by varying the working parameters the flow instability boundary can be calculated. For a more in-depth study of density wave oscillations in heated pipes, the unstable boundary characteristics were analysed computationally for different influences such as pressure, mass flow rate, inlet subcooling degree and pipe geometry on the basis of model validation. In addition, the Nyquist function was used in Matlab to plot the Nyquist curve for different influencing factors and to analyse the stability margins for specific operating conditions. The unstable boundary characteristic diagram was obtained when the pressure was 5–10 MPa and the mass flux was 300–1300 kg·m−2·s−1. The calculated data was collated and mass flow rate and heat load boundary diagrams were plotted, which could visualise the boundary characteristics of the density wave oscillations under different operating conditions. In order to make the calculation results more applicable, Nsub and Npch were used to construct the dimensionless unstable boundary characteristic diagram. Results showed that the influence of inlet subcooling degree on flow stability is non-monotonic. In addition, the effects of factors such as pressure, mass flow rate and inlet throttling coefficient are monotonic.

Measurements and analysis of rotational temperatures obtained with Raman and optical emission spectroscopy in a nonequilibrium nitrogen plasma

Rotational temperature measurements of N2(B3Πg), N2(C3Πu) and obtained by optical emission spectroscopy (OES) are compared with previous gas temperature measurements obtained with Raman spectroscopy in a nonequilibrium recombining nitrogen plasma at atmospheric pressure. The plasma is produced in a state of thermal and chemical equilibrium at about 7000 K using an inductively coupled plasma torch. It is then forced out of chemical equilibrium by imposing rapid cooling through a water-cooled tube. The gas temperature measured by Raman spectroscopy is about 3200 K at the exit of the tube. The rotational temperatures of N2(B) and N2(C) measured with OES are found to be in good agreement with the gas temperature, but the rotational temperature of N2 +(B) is found to be significantly above the gas translational temperature. We propose that this higher rotational temperature is the result of N2 +(B) being formed by the charge exchange reaction between N2(A3Σu +) and N+. Kinetic and QSS simulations are performed to support this assumption and a rate constant for this reaction is proposed.

Experimental study of recombining nitrogen plasmas: II. Electronic population distributions and nonequilibrium radiation of atoms

We present optical emission spectroscopy measurements from the vacuum ultraviolet to the near-infrared in a recombining nitrogen plasma flow. An inductively coupled plasma torch is used to create an equilibrium plasma at atmospheric pressure. This plasma is then forced to recombine by flowing through a water-cooled tube. For certain conditions, the plasma is forced out of chemical equilibrium. The emission of excited nitrogen atoms, essential for reentry radiation, is measured to study the nonequilibrium distributions of the electronic states. The densities of the low-lying energy states are found to follow a Boltzmann distribution while the high-lying states are closer to a Saha–Boltzmann distribution—consistent with previous predictions of recombining nonequilibrium plasmas. The measured densities are then compared with the predictions of a two-temperature model, which is found to underpredict the measured densities. The total measured radiation is around 5 orders of magnitude stronger than the equilibrium radiation. The 2-T model estimate of this radiation is much closer yet still underestimates the measured radiation. A model using a single electronic temperature is therefore not sufficient to predict the measurements. The measurements presented in this paper will be useful to test more detailed state-to-state recombination models.

Predicted Heat Flux Performance of Actively Cooled Tungsten-Armored Graphitic Foam Monoblocks

Tungsten (W)–armored graphitic foam monoblocks were developed for applications requiring high-Z plasma-facing material in long-pulse fusion experiments and ultimately deuterium-tritium fusion reactors. The monoblocks are an integrated material system combining the advantages of a chemical vapor deposited (CVD) W coating with a high-conductivity graphitic foam. The W is a high-melting-point, high-Z material with low tritium retention. The graphitic foam coupled to a swirl tube serves as a high-thermal-conductivity heat sink that cannot melt, although it can sublime at much higher temperatures than copper melts. Together, they comprise a robust plasma-facing component (PFC) weighing roughly 5% of an all-W component or 17% of a traditional W-coated copper heat sink. A single-channel mock-up consisting of four graphitic foam monoblocks equipped with a water-cooled swirl tube was fabricated for eventual testing in the 60-kW, EB-60, rastered electron beam at the Applied Research Laboratory of The Pennsylvania State University. Two monoblocks have a thin 50-μm-thick coating of pure W chemically vapor deposited over NbC and pure Nb interlayers. Two others have a 2-mm-thick pure W coating CVD on graphitic monoblocks using the same interlayers. The mock-up will be cooled with available 10 m/s, 0.7 MPa water with a 22°C inlet temperature and subjected to varying uniform heat loads up to 20 MW/m2. It is equipped with type-K thermocouples at various depths, and calibrated infrared thermography and spot pyrometry will be used to characterize the heated surface. Real-time water calorimetry will be used to ascertain the absorbed steady-state power and infer the heat flux during testing. Since testing cannot be done under prototypic divertor flow conditions, it is necessary to predict the thermal response of this novel PFC system and investigate the power sharing between radiation and convection at divertor heat flux levels and its inherent ability to avoid critical heat flux. Results are reported for predictions obtained from computational fluid dynamics models up to 30 MW/m2 of steady-state uniform heat flux. Leading-edge heat loads of 30 MW/m2 on a 2-mm-wide side strip were also investigated to ascertain if coating delamination is likely.

Location of the Leakage From a Simulated Water-Cooling Wall Tube Based on Acoustic Method and an Artificial Neural Network

Water-cooling wall tube leakage accident is an important factor affecting the safe and economic operation of power station boilers. In this article, the acoustic method is applied to locate the leakage from a simulated water-cooling wall tube, and several key technologies are studied in order to identify the precise location of leakage source. Sound wave propagation path in ‘nonuniform temperature field is obtained to overcome the shortcoming that the traditional location technology always assumed that sound waves propagate along the straight line. Considering the refraction effect of sound waves, the reconstruction method based on radial basis function approximation with polynomial reproduction (RBF-PR) is used to reconstruct the temperature field. A generalized cross correlation with second correlation is applied to estimate the time delay of arrival (TDOA). According to the temperature field measured by acoustic method and the propagate time of sound waves, the location fingerprint method including the statistical correlation characteristics between the coordinate of fingerprint points and TDOA are constructed. Radial basis function artificial neural network (RBF ANN) is used to estimate the coordinate of leakage point. Numerical simulations and experimental study are implemented to evaluate the effectiveness of the proposed location system. An acoustic location test platform is constructed to study the location accuracy in different working conditions. The results indicate that considering the refraction effect, the reconstruction performance of temperature field is superior than that without the refraction effect, and acoustic method with RBF ANN algorithm can gain the leakage location with high accuracy and good antinoise ability in the above high-quality reconstructed nonuniform temperature distribution.