Metal Temperature Research Articles

Experimental Investigations and Qualification of Innovative Flow Sensors in the 1000 K SOLTEC-2 Sodium Loop

Liquid metals, such as sodium, have been already successfully used as heat transfer fluids (HTF) in concentrating solar power (CSP) plants up to ~550 °C. Even higher temperatures can be achieved and are envisioned for future CSP plants. The lack of measuring flow rate devices at high temperatures for liquid metals motivated this study. The present paper presents the experimental mock-up and the experimental results obtained with the SOLTEC-2 facility for two test flow sensors, one innovative eddy current flow sensor (ECFM) developed at HZDR, Germany and a built-in permanent magnet fly-wheel sensor for runs up to a sodium temperature of 700 °C. The signals of the sensors are compared also against the power level of the sodium pump.

On the Microstructure and Properties of Complex Concentrated bcc Solid Solution and Tetragonal D8m M5Si3 Silicide Phases in a Refractory Complex Concentrated Alloy

In this work, the refractory complex concentrated alloy (RCCA) 3.5Al–4Cr–6Ge–1Hf–5Mo–36Nb–22Si–1.5Sn–20Ti–1W (at.%) was studied in the as cast and heat treated conditions (100 h or 200 h at 1500 °C). There was strong macrosegregation of Si in the 0.6 kg button/ingot of the cast alloy, in which A2 solid solution, D8m βNb5Si3, C14-NbCr2 Laves phase and Tiss and a ternary eutectic of the A2, D8m and C14 phases were formed. The partitioning of Ti in the as cast and heat treated microstructure and its relationships with other solutes was shown to be important for the properties of the A2 solid solution and the D8m βNb5Si3, which were the stable phases at 1500 °C. The near surface microstructure of the alloy was contaminated with oxygen after heat treatment under flowing Ar. For the aforementioned phases, it was shown, for the first time, that there are relationships between solutes, between solutes and the parameters VEC, Δχ and δ, between the said parameters, and between parameters and phase properties. For the contaminated with oxygen solid solution and silicide, trends in relationships between solutes, between solutes and oxygen content and between the aforementioned parameters and oxygen content also were shown for the first time. The nano-hardness and Young’s modulus of the A2 solid solution and the D8m βNb5Si3 of the as cast and heat-treated alloy were measured using nanoindentation. Changes of nano-hardness and Young’s modulus of the A2 solid solution and D8m βNb5Si3 per solute addition for this multiphase RCCA were discussed. The nano-hardness and Young’s modulus of the solid solution and the βNb5Si3, respectively, were 9.5 ± 0.2 GPa and 177.4 ± 5.5 GPa, and 17.55 ± 0.5 GPa and 250.27 ± 6.3 GPa after 200 h at 1500 °C. The aforementioned relationships and properties of the two phases demonstrated the importance of synergy and entanglement of solutes, parameters and phases in the microstructure and properties of the RCCA. Implications of synergy and entanglement for the design of metallic ultra-high temperature materials were emphasised.

The analysis of the stability of the Cauchy problem in the cylindrical double-layer area

Ceramic protective coats, for instance, on turbine blades, create a double-layer area with various thermophysical properties and they require metal temperature control. In this paper, it is implemented by formulating a Cauchy problem for the equation of thermal conductivity in the metal cylindrical area with a ceramic layer. Due to the ill posed problem, a regularization method was applied consisting in the notation of thermal balance for the ceramic layer. A spectral radius for the equation matrix was taken as the stability measure of the Cauchy problem. Numerical calculations were performed for a varied thickness of the ceramic layer, with consideration of the non-linear thermophysical properties of steel and a ceramic layer (zirconium dioxide). A polynomial was determined which approximates temperature distribution in time for the protective layer. The stability of solutions was compared for undisturbed and disturbed temperature values, and thermophysical parameters with various ceramic layer thickness. The obtained calculation results confirmed the effectiveness of the proposed regularization method in obtaining stable solutions at random data disturbance.

Unravelling the Factors Influencing Halide Perovskite Based Switchable Photovoltaics

AbstractLead halide perovskites have revolutionized the field of optoelectronics (such as photovoltaics and light emitting diodes) demonstrating extraordinary material properties despite being formed at low temperatures. However, ion migration in the bulk or at the interfaces results in stability issues especially in devices where metal electrodes directly interface with the perovskite film. Utilizing the switchable photovoltaic phenomenon (SPV) in halide perovskites as a measure of ion migration and electrochemical reactions within them, Cs0.05MA0.15FA0.70PbI2.5Br0.5 triple cation perovskite, widely used in photovoltaics is evaluated. The various factors determining the SPV, including electric field magnitudes, type of metal contacts, Illumination conditions, and temperature is systematically measured. This study reveals the roles of electrode work functions and reactivities on ion migration and local electronic structure modulation. ITO electrodes demonstrated the highest open‐circuit voltage (Voc) about 0.85 V while Ag electrodes developed conductive filaments. However, the Voc distribution for Ti and Cr electrodes shows a more pronounced linear correlation with the poling electric field strength. Insights from this lateral design are directly relevant to transistor and memristor architectures and offer inputs into the design of perovskite‐based photovoltaic/optoelectronic devices.

Prediction of radiation embrittlement of VVER-1000 RPV welded seam material at lifetime extension up to 60 years and more

The correctness of the model assumption about additivity of the contributions of hardening (formation of dislocation loops and radiation-induced precipitates) and non-hardening (formation and accumulation of grain boundary segregations) mechanisms to the final radiation embrittlement of VVER-1000 RPV weld materials has been verified. The paper presents the results of the experiment to obtain predicted values of the critical embrittlement temperature of weld metal with nickel content of 1.59–1.88% using accelerated irradiation in the IR-8 research reactor from states characterized by different starting level of grain boundary segregation. The procedure of accounting for the flux effect for the values of critical embrittlement temperature obtained using accelerated irradiation has been proposed. The conservativity of the weld metal radiation embrittlement dependence has been verified based on the modal assumption of additivity of the contributions of the strengthening and non-strengthening mechanisms up to the values of fast neutron fluence ~75–1022 neutrons/m2.

Application of Red Mineral Soil As Adsorbent for Removing Cd (II) Metal Ion from Synthetic Waste Water

This study investigates the adsorption of Cadmium (II) ions onto red mineral soil. The red mineral soil has been applied as an adsorbent for the treatment of Cadmium contaminated synthetic waste water. The adsorption study was conducted based on the parameters of pH, initial metal ion concentration, dosage amount, contact time, and temperature.

Recyclable magnetic nickel ferrite–carboxymethyl cellulose–sodium alginate bio-composite for efficient removal of nickel ion from water

In waste water treatment, magnetic bio-composites are frequently investigated as an adsorbent recently due to their great capacity for adsorption and affordability. In this current work, an attempt has been made to develop spinel nickel ferrite–carboxymethyl cellulose (NiFCMC) composite and modified its surface by alginate polymer to form NiFCMC–Alg composite. Several techniques were utilized to characterize these adsorbents including Fourier transform infrared spectroscopy, x-ray diffraction, field emission scanning electron microscopy, energy-dispersive spectra, thermogravimetric analysis, vibration sample magnetometry and pH of point zero charge. These adsorbents were explored to check their potentiality to remove Ni (II) ions in aqueous medium on various parameters such as contact time, initial metal ion concentration, pH, adsorbent dose and temperature. The optimum time for establishment of equilibrium was 180 minutes at pH 8 with adsorbent dose of 0.1 g. Results of kinetic studies revealed that the best fit for the metal ion adsorption data was the Lagergren pseudo-second-order mode indicating the chemisorption nature. Likewise, the Langmuir isotherm model also showed good agreement with adsorption equilibrium data with maximum adsorption capacities 47.84 ± 2.39 and 60.24 ± 3.01 mg/g for NiFCMC and NiFCMC–Alg respectively. The calculated adsorption thermodynamic parameters confirmed the spontaneous nature of adsorption process. The regeneration efficiency of both adsorbents was studied for five cycles and showed significant results. This study has shown that NiFCMC and NiFCMC–Alg can be a good substitute for removing Ni (II) ions in aqueous medium.

The influence of weld fluid flow on the formation mechanism of intermetallics and HfO2 precipitates in dissimilar electron beam welding of C-103 niobium alloy to nickel

In this research, the effect of weld fluid flow in molten pool on the formation and behavior of intermetallic compounds NbNi3 and Nb7Ni6 and HfO2 precipitates in dissimilar electron beam welding of niobium base alloy C-103 to nickel was investigated. It was observed that due to the large difference in the melting temperature of the base metals, nickel contributed 82% by volume and C-103 contributed 18% by volume in weld zone. In the weld zone and attached to the C-103 base metal, a thin and continuous intermetallic zone was formed, including the initial phase of NbNi3 and the eutectic structure of NbNi3+Nb7Ni6. In the areas after the continuous intermetallic layer in welding, the initial phase of NbNi3 and the eutectic structure of NbNi3+γ-Ni are formed. During welding, HfO2 particles in the C-103 base metal enter the molten pool due to the weld fluid flow and remain as white precipitates in the welding zone and close to C-103. In addition to these precipitates, nanometer precipitates of HfO2 are also observed in the weld, which are formed in-situ in the weld due to the reaction of hafnium with dissolved oxygen in the melt. In the central zone of the weld, continuous band-shaped intermetallic layers can be observed which have been removed from the wall of C-103 due to the fluid flow of the molten pool and moved towards the central zone of the weld. These layers act as nucleus in the center of the molten pool and solidification occurs from their surface. At first, solidification begins with the planar growth of the initial phase of NbNi3, and then cellular and columnar dendritic growth occurs. At the end of solidification, the eutectic structure of NbNi3+γ-Ni forms between cells and dendritic branches. Due to the presence of intermetallic compounds NbNi3 and Nb7Ni6 as well as HfO2 nanometer precipitates in the weld, the hardness of the weld zone was higher than that of the base metals.

Механічні властивості аморфних металевих сплавів системи Al87(Ni,Fe)8(REM)5 після короткочасного відпалу

The phase transition temperatures for amorphous metals based on aluminum Al87(Ni,Fe)8(REM)5 system were determined by differential scanning calorimetry (DSC). The mechanisms of formation and growth of nanocrystals in an amorphous matrix were predicted using kinetic models (Matusita model). It was found that after annealing at the temperature of stable nanocrystalline growth, an X-ray amorphous structure with a volume fraction of disordered nanocrystalline phases of solid state of Al(X), GdFe2, AlFe2Ni, GdFe2 for the amorphous metal alloy (AMA) Al87Y4Gd1Ni4Fe4 alloy and microcrystalline phases of solid state of Al(X), GdFe2 AlFe2Ni for the Al87Gd5Ni4Fe4 alloy are formed, which significantly affects the mechanical properties of the Al87(Ni,Fe)8(REM)5 system. The effect of annealing on the mechanical properties of amorphous aluminum-based alloys was investigated using Oliver-Pharr and Young's modulus methods it was found that thermal modification of AMAs: Al87Gd5Ni4Fe4 as a result of heat treatment of AMAs from 5 to 15 min., the microhardness increases from 0.20 GPa to 2.75 GPa, and when heat treated for 60 min at a temperatures of T3 = 645±5 K, 647±5 K, it decreases to 0.35 GPa and 0.45 GPa, respectively.

Castor seed-derived luminescent carbon nanoparticles for metal ion detection and temperature sensing applications

In the current study, castor seeds are used as a first-time natural precursor in the hydrothermal process of making carbon nanoparticles. The produced nanoparticles have a non-uniform size distribution with an average diameter of 13 nm and a roughly spherical shape. They comprise a variety of functional groups containing carbon, nitrogen, and oxygen. Their spectra have peaks at 524 nm and 441 nm for their emission and excitation, respectively. They exhibit temperature-sensitive Photoluminescence (PL) behaviour, high quantum yield value (24%), and excitation-dependent emission. In high salt environments, UV radiation, storage time, and fluorescent light they provide exceptional photostability. They have been used in applications for metal ion and thermal sensing. With a limit of detection (LOD) value of 18 μM, they are found to be both sensitive and selective to Fe3+ ions. Additionally, a nanothermosensor with good recovery and a broad temperature range (5 °C–85 °C) has also been demonstrated with a thermal sensitivity of 0.54% °C−1 based on their temperature-sensitive behaviour.

Surface activity and micellization of streptomycin sulfate and diphenhydramine hydrochloride in the presence of alkali and alkaline earth metal chlorides

ABSTRACT The study investigated the surface tension of the surface-active drugs streptomycin sulfate and diphenhydramine hydrochloride using three uni-univalent and three bi-univalent electrolytes: NaCl, KCl, and RbCl (0.01 mol.kg−1), and MgCl2, CaCl2, and SrCl2 (0.002 mol.kg−1) over a temperature range of 298.15 to 313.15 K. Surface tension determination has proven instrumental in examining the micellization and surface-active properties of these drugs in the presence of specific electrolytes. The surface tension values of these drugs exhibit a decrease in magnitude with increasing drug concentration, particularly noticeable in streptomycin sulfate. This phenomenon can be elucidated by considering the delicate balance between hydrophobic and hydrophilic forces within the system. Additionally, the impact of the nature of metal halides and temperature on surface tension magnitude has been scrutinised, with interpretations focused on alterations in size. From surface tension values, the interfacial parameters, such as Γ max , A min , and π CMC were examined. The results indicate a strong affinity between drug-electrolyte molecules that reduces the surface tension values. The CMC relations govern the hydrophobic and hydrophilic interactions in the ternary system of water-drug-electrolyte. The thermodynamics of micellization explains the work done for micellization and illuminates the surface and bulk properties of drugs.

Distribution and Characteristics of Residual Stresses in Super Duplex Stainless Steel Pipe Weld

This paper explores the distribution and features of residual stresses formed by super duplex stainless steel pipe welding. Experimental investigations, which encompass an elevated temperature tensile test and metallographic observation along with a hardness test and residual stress measurement, were first conducted to obtain the mechanical properties at high base metal temperatures and to confirm whether or not the duplex stainless steel undergoes martensitic phase development during the welding process. Finally, experiments were performed to scrutinize the residual stress evolution through the metallurgical phase transformation in the weld region and its vicinity. A sequentially coupled 3D thermal, mechanical and metallurgical finite element (FE) model capable of incorporating the experimental consequences was established next. A 3D FE simulation of the girth welding process was conducted, and the axial and hoop residual stress profiles along the girth were evaluated. The results substantiate that martensitic phase evolution occurs in the process of cooling during the welding of super duplex stainless steel, and they also highlight the significance of taking the metallurgical phase transformation into account in the numerical reproduction of the girth welding process for the accurate expression of weld-induced residual stresses, which is especially important for precisely predicting hoop residual stresses.

Preparation and characterization of CS/PAT/ MWCNT@MgAl-LDHs nanocomposite for Cd2+ removal and 4-nitrophenol reduction.

The present study evaluated the performance of multiwalled carbon nanotube (MWCNT)@MgAl-layered double hydroxide (LDH) nanoparticles loaded on poly-2 aminothiazole (PAT)/chitosan (CS) matrix (CPML) to remove Cd2+ ions from aqueous solution. The removal efficiency of modified CS/PAT with MWCNT@MgAl-LDHs was increased significantly compared to pure CS/PAT. The influence of heavy metal ion concentration, pH, temperature, adsorbent dosage, and contact time on the adsorption was examined. The optimum conditions for the adsorption of Cd2+ ions were 25 0C with the adsorbent dosage of 0.06g and initial concentration for adsorption of the Cd2+ 100mg/L at pH = 8. The maximum adsorption capacity was measured to be 1106.19mg/g. The values of thermodynamic parameters namely Gibbs free energy (ΔG°), entropy change (ΔS°), and enthalpy change (ΔH°) indicated the feasibility, spontaneity and the endothermic nature of the adsorption process, respectively. The pseudo-second-order kinetics and the Langmuir model were selected as the best models for the adsorption process. Also, CPML nanocomposite (NC) was successfully tested for p-nitrophenol (p-NP) reduction in the presence of NaBH4. The reaction was nearly completed in 6min. The fabricated CPML-NC could be reused for three consecutive cycles.

Computationally Efficient Workflow for Conjugate Heat Transfer With Large Eddy Simulation for Gas Turbine Combustors

Abstract Typical gas turbine combustor (GTC) and high-pressure turbine stage generally employs 10,000 to 100,000 small passages of cooling holes. Such an arrangement protects the solid walls through impingement and effusion cooling. The former provides solid wall internal cooling, and the latter helps to reduce the metal temperature by developing a thin film around it. High-fidelity simulations are primarily utilized in the industry such that accurate prediction from numerical tools can aid advancement in the performance of such machines. In this paper, a numerical study using ansys fluent has been conducted with large eddy simulation (LES), conjugate heat transfer (CHT), and radiation to explore the relative benefits of implicit and explicit fluid–solid thermal couplings. The simulations of LES with CHT are performed for well-documented experiments of heated nozzle exhaust passing over a film-cooled plate (Wernet et al., 2020, “PIV and Rotational Raman-Based Temperature Measurements for CFD Validation of a Perforated Plate Cooling Flow: Part I,” AIAA 2020-1230, Session, AIAA Scitech 2020 Forum, Orlando, FL, Jan. 6–10, 2020). The accuracy of the modeling approach is assessed by comparing CHT predictions of fluid velocity and solid-plate temperatures with experiments. Acceleration techniques for LES–CHT simulations are explored in this paper with an emphasis on thermal coupling, radiation, etc. The effects of mesh sensitivity and flow solution approach are presented in detail. LES–CHT results generally match the experiments at various blowing ratios both qualitatively and quantitatively. The comparisons in the paper allow the selection of best practices for CHT modeling in GTC. A generic combustor model with effusion cooling hole arrays is used in the paper to establish the workflow for modeling LES with CHT in the industrial-type combustor. Various acceleration techniques are utilized to show an overall improvement in solution performance with the same level of accuracy.

Study on coupled heat transfer model and enhanced heat transfer law of liquid metals and supercritical fluids

ABSTRACT The supercritical carbon dioxide Brayton cycle system is being considered for application in the power conversion system of advanced liquid metal fast reactors. One important research topic is the coupled heat transfer characteristics and enhanced heat transfer laws between liquid metals and supercritical fluids. However, the traditional Reynolds analogy hypothesis with a constant turbulent Prandtl number is difficult to satisfy the numerical conjugate heat transfer research of liquid metals and supercritical fluids. Therefore, based on the open-source computational fluid dynamics program OpenFOAM, a numerical method suitable for the coupled heat transfer calculation of liquid metals and supercritical fluids was developed, which can achieve precise conjugate heat transfer solutions by applying different turbulence models and heat flux models to liquid metals and supercritical fluids. Subsequently, based on this method, the coupled heat transfer behavior of liquid metals and supercritical fluids in the straight channel of a typically printed circuit heat exchanger was studied. The focus was investigating the conjugate heat transfer characteristics of liquid heavy metal lead-bismuth eutectic and liquid metal sodium with supercritical carbon dioxide. Some sensitive results, including the inlet temperature and Reynolds number of liquid metals and supercritical fluids, were qualitatively and quantitatively analyzed.

Adsorption of Cu (II) ions from aquatic environment using pre-irradiated Ethylene Tetrafluoroethylene Film

Although copper (Cu) is a very beneficial metal, having too much of it in the body can cause lung issues, severe anemia, nausea, and vomiting. In order to extract Cu (II) ions from aqueous solution, an adsorbent was constructed in this study employing pre-irradiation grafted Ethylene tetrafluoroethylene (ETFE) film. The grafting method was used to binary monomers of sodium styrene sulfonate (SSS) and acrylic acid (AA), where NaCl served as an additive. The grafted polymer was also subjected to studies of tensile strength, water uptake, surface area extension, Scanning Electron Microscopy (SEM), and Fourier Transform Infrared spectroscopy (FTIR). The adsorption of Cu (II) was investigated with respect to pH, starting metal ion concentrations, contact time, monomer concentrations, and temperature. With 50 kGy of radiation dose, 4% NaCl, and 30% of monomer solution (SSS:AA = 1:2) in water generated the highest graft yield of 470%. The maximum adsorption capacity (412 mg g−1) was discovered with an initial concentration of 2500 mg L−1, a pH of 4.86, and a contact time of 24 h at room temperature (25 ℃). A monolayer adsorption was recommended by the good linking between experimental data and the Langmuir Isotherm Model. The kinetic adsorption data closely fitted with the pseudo-second-order reaction. Due to its increased adsorption capacity and reusability, the synthesized new grafted polymer can be considered an efficient adsorbent for Cu (II) removal from wastewater.

Sequential estimation of high temperatures of liquid metals by using particle filter methods

This work follows up our previous studies dedicated to the estimation of the transient temperature of niobium and 100c6 steel samples, in ranges that include solid and liquid phases, as well as phase changes. In the experimental setup, a metallic sample of few millimeters is aerodynamically levitated and then heated by a powerful laser, while a collimator focused on the sample collects the radiative flux that is split towards five pyrometers of different wavelengths. The measured spectral fluxes are used in an inverse analysis to estimate the sample temperature. Difficulties in the inverse problem solution related to the dependence of the sample emittance with temperature and wavelength could be overcome by reducing the number of model parameters using a simple linear variation of the emittance with respect to the wavelength. In this work the transient temperature of the sample is estimated sequentially by solving a state estimation problem with two algorithms of the particle filter method, namely: the Sampling Importance Resampling (SIR) and Auxiliary Sampling Importance Resampling (ASIR) algorithms. Results obtained with these algorithms and the radiative spectral fluxes exhibited small discrepancies with respect to the temperature measurements of a reference bichromatic pyrometer.

Machine learning guided tuning charge distribution by composition in MOFs for oxygen evolution reaction.

Traditional design/optimization of metal-organic frameworks (MOFs) is time-consuming and labor-intensive. In this study, we utilize machine learning (ML) to accelerate the synthesis of MOFs. We have built a library of over 900 MOFs with different metal salts, solvent ratios, reaction durations and temperatures, and utilize zeta potentials as target variables for ML training. A total of four ML models have been used to train the collected dataset and assess their convergence performances, where Random Forest Regression (RFR) and Gradient Boosting Regression (GBR) models show strong correlation and accurate predictions. We then predicted two kinds of MOFs from RFR and GBR models. Remarkably, the experimentally data of the synthesized MOFs closely matched the predicted results, and these MOFs exhibited excellent electrocatalytic performances for oxygen evolution. This study would have general implications in the utilization of machine learning for accelerating the synthesis of MOFs for diverse applications.

Kinetic and Equilibrium Modelling of Lead, Zinc and Copper Ions Sorption from Aqueous Solution Using Charcoal Fines

The potential of chemically modified charcoal fines UCF (unmodified charcoal fine) and MCF (modified charcoal fines) as low cost adsorbents for the removal of Pb2+, Cu2+ and Zn2+ ions from aqueous solution was studied. MCF was prepared by chemical modification of UCF with HNO3 and KOH followed by pyrolysis. The factors influenced the effectiveness of biosorption process were pH, contact time, initial metal concentration, temperature and adsorbent dosage. FT–IR spectra confirmed the existence and interaction of the adsorbents with the effluent pollutants. MCF exhibited optimum pH, temperature, contact time, initial metal ion concentration and biosorbent dosage values of 5, 35 0C, 90 minutes, 15 mg/L and 2 g, respectively. UCF exhibited optimum pH, temperature, contact time, initial metal ion concentration and biosorbent dosage values of 6, 35 0C, 100 minutes, 20 mg/L and 2.5 g, respectively. The adsorption isotherm modelling using both adsorbents showed that the equilibrium data conformed more to Langmuir than the Freundlich model. Kinetic studies showed that the adsorption processes followed a pseudo-second order kinetic model. Thermodynamic studies confirmed the spontaneity and feasibility of the adsorption process. The results showed that both adsorbent have the potential to be applied as alternative low cost biosorbent.

Hot metal temperature prediction technique based on feature fusion and GSO-DF

Hot metal temperature prediction technique based on feature fusion and GSO-DF