Pin Temperature Research Articles

Analysis of tribological behavior, pin temperature, and surface roughness of a brake pad material with nano coating

The present work is concentrated on the novel multi-nano particle coating of CoNiCrAlY matrix on brake pad material. The tribological behavior of plasma sprayed CoNiCrAlY particle composite coating with nano inert particles like ZrO2, Al2O3, and AT40 were compared. A comparison was made with respect to structure and morphology of coating. The coatings were characterized with Scanning electron microscopy(SEM) and Energy dispersive X-ray spectroscopy(EDAX) technique. The tribological performance of these coatings were studied using pin-on-disc test rig under dry sliding conditions. The wear study revealed CoNiCrAlY+nano Al2O3 particle coating showed better specific wear rate compared to ZrO2 and AT40 composite coating. The observed tribological behaviour is very much influenced by the ability of nano particles to get distributed in the CoNiCrAlY matrix. The CoNiCrAlY coating with nano particles showed significant specific wear resistance of brake pad material. They coated samples also resulted in minimum rise in pin temperature. This is attributed to the homogeneous distribution of nano particles in the coating. These composite coating also showed lower coefficient of friction values. Although referring to other simplified and extreme conditions, the results obtained provides a new window for using nano hard coatings to enhance the life and efficiency of the commercially available four-wheel vehicle brake pad.

Corrosion, wear and machinability studies on scrap aluminium alloy wheel based metal matrix composite

Recycled materials, especially scrap aluminum alloy wheels with reinforcement castings, are gaining applications in various fields such as aerospace, naval, military, and automobile. In this research, Honda car alloy wheels are stir-cast with 5% alumina as reinforcement and subjected to corrosion, wear, and machinability studies. Corrosion studies were conducted to evaluate the corrosion current density (ICorr), corrosion potential (ECorr), and corrosion rate for the cast aluminum metal matrix composite. The wear studies with different loads, i.e., 50 N, 60 N, 70 N, and 80 N, were performed on the specimen and investigated the coefficient of friction, frictional force, and pin temperature. The sliding load has a significant effect on wear performance, and for the sliding load of 80 N, the wear recorded was 2574.83 µm. The electrochemical machinability studies with voltage, duty cycle, and concentration of citric acid electrolyte are performed on the machining rate and surface corrosion factor. Analysis of the electrochemical machining process with PROMETHEE-II shows that 7 V, 60% duty cycle, and 30 g/L electrolyte concentration are estimated to be the best combination for a higher machining rate and a lower surface corrosion factor. KEY WORDS: Alumina, Machining rate, Nyquist plot, Electrochemical machining, PROMETHEE-II Bull. Chem. Soc. Ethiop. 2024, 38(4), 1163-1175. DOI: https://dx.doi.org/10.4314/bcse.v38i4.27

Study on pin temperature and wear behaviour of plasma sprayed Ni-Cr coatings with nano Al2O3 particle

ABSTRACT In this study, the dry sliding wear behaviour of plasma sprayed composite Ni-Cr coatings with nano Al2O3 particle concentrations of 0, 5, 10, 15, 20, and 100 wt.% on Al6061 substrate material was analysed. The coatings were characterised by scanning electron microscopy. The results showed higher porosity and coating thickness values for 100% and 20% nano Al2O3 particle coatings. The microhardness was found to increase with an increase in nano Al2O3 particle concentration in the Ni-Cr coating matrix. The porosity values were found to decrease with an increase in coating thickness. It is found that the specific wear rate of the Ni-Cr/15% Al2O3 particle coating is reduced by 54.02% compared to the Al2O3 particle coating.

Irregular, Backward-Compatible PWR Assembles with More Pins to Facilitate Uprates

Increasing the number of pins within a pressurized water reactor (PWR) assembly reduces pin temperature for a given assembly power. In conjunction with a core retrofit, this presents a potential route to PWR uprate, which is of growing interest given recent increases in electricity prices. However, most PWRs utilize regular lattice designs with fixed guide tube positions, such as the very common 17 × 17 lattice design with 25 guide/instrumentation tubes. These tubes are aligned with penetrations in the reactor pressure vessel, which presents a prohibitive obstacle to retrofit, and more widely, may “lock” many PWRs to this particular fuel configuration. In this paper, an irregular PWR fuel assembly is proposed. It is shown that a backward-compatible lattice with 324 fuel pins per assembly (BL324), uniform enrichment, and the same hydrogen-to–heavy metal ratio as a reference 17 × 17 assembly with 264 fuel pins can achieve within-assembly power peaking within 2% of the reference assembly under equivalent conditions while fixing the guide tube positions. Power peaking can be further reduced to reach that of the existing fuel assembly by reducing the enrichment of 36 of the pins by 0.2 wt%. The fuel assembly could potentially either support a significant uprate of up to ~20% in conjunction with low-enriched uranium plus (LEU+) fuel or a more aggressive cycle design, and hence, improved discharge burnup at the same power and batch strategy. A subchannel analysis shows that the coolant heat-up distribution is comparable to the reference assembly. However, the pressure drop is estimated to be 4% higher, which would challenge the performance of transition cores containing both 17 × 17s and BL324s. Further incremental changes to BL324 may be attractive, either to improve manufacturability or to slightly improve performance through formal optimization.

Effect of sub-cooling on fuel channel behaviour during LOCA for Indian PHWR

During LOCA with ECCS failure, the removal of decay heat from the channel to a moderator plays a significant role in determining the fuel bundle temperatures. An experimental investigation has been carried out to study the effect of change in moderator temperature (65 ℃, 75 ℃, and 85 ℃) on the fuel channel at a steady state of 900 ℃ center pin temperature. The results show that at different moderator temperatures, there is insignificant variation in the temperature of PT, whereas for CT appreciable temperature gradient has been observed. The maximum heat transfer coefficient for CT was attained at 65 ℃ moderator temperature. Even with an increase in moderator temperature, channel integrity is maintained, and the moderator acts as an ultimate heat sink for all three moderator temperatures.

Simulation of Temperature Distribution in a Brake Pad Ceramic Composite Material

The temperature distribution is an important aspect of any brake pad composite material. The braking temperature affects the performance and efficiency of any brake pad composite material. It is difficult to measure the interface temperature between the brake pad and disc by thermocouples or infrared thermal sensors during braking. This work investigates the temperature distribution of a ceramic composite brake pad material by the transient thermal analysis method. The transient thermal approach method helps to visualize the interface temperature through simulation. Also, it provides pin temperature at a distance of 4 mm and 6 mm away from the disc surface to observe the temperature distribution of the brake pad. The experimental values of the temperature of the pin at 4 mm and 6 mm away from the disc are collected from the literature and compared with the predicted temperature through simulation. It is found that there is a close agreement between the predicted and experimental temperature values.

Effect of the pin temperature and SiC reinforcement on dry sliding tribological behavior of aluminium based silicon carbide metal matrix composite (Al-SiC) using Taguchi approach

This paper deals with the replacement of existing brake pad material based on its highest strength and stiffness-to-weight ratio. To overcome this problem, we have investigated the input process parameters: silicon carbide weight percentage, normal pressure, sliding speed or distance, and temperature, all of which affect tribological properties. The tribological behavior of an aluminum-based silicon carbide metal matrix (Al-SiC) is investigated at elevated temperatures in this study. The metal matrix composite brake pad material has been introduced recently due to its cost-effectiveness, stable coefficient of friction, lower wear rate, and constant contact pressure at high temperatures. In this investigation, an LM25-SiC composite was fabricated using the stir casting technique, in which SiC particles were reinforced at 5%, 10%, and 15% by weight in the base alloy LM25. The investigation was carried out for friction and wear studies on a pin on a disc tester at elevated temperatures for different loads and sliding distances. The investigation using the design of experimentation highlighted by the Taguchi technique highlights the effectiveness of replacing existing brake pad material. The experimental results show improved mechanical properties due to the addition of SiC, and it is also observed that a 15% SiC addition to base metal gives optimal sliding wear.

Burç ve Yatak Uygulamaları için Saf Poli-eter-eter-keton Polimer ve Karbon Elyaf Takviyeli Poli-eter-eter-keton Kompozitin Sürtünme ve Aşınma Performanslarının Karşılaştırılması

Endüstrinin değişik alanlarında, makinelerin bazı aksamlarında plastik malzemeden üretilen burç, makara ve rulman gibi makine elemanları kullanılır. Bu makine elemanlarına bazen kullanım şartlarına bağlı olarak farklı yükler etki etmekte bazen de bu parçalar farklı hızlarda çalışmaktadır. Etki eden şartlara bağlı olarak malzemenin çalışma ömrü belirlenir. Bu çalışmada, saf poli-eter-eter-keton (PEEK) polimeri ile ağırlıkça %30 oranında karbon elyaf (CE) takviyeli poli-eter-eter-keton (PEEK-30KE) kompozitin tribolojik performansları araştırılmıştır. Tribolojik deneyler disk üzerinde pim cihazı kullanılarak oda sıcaklığında ve kuru kayma şartlarında gerçekleştirilmiştir. Deneylerde 30N ve 100N olmak üzere iki farklı yük, 1, 2, 3 ve 4m/s olmak üzere dört farklı hız kullanılmıştır. Deneyler sonucunda saf PEEK polimer ve %30 oranında karbon elyaf takviyeli PEEK kompozitinin sürtünme katsayısı, pim sıcaklığı ve spesifik aşınma oranı belirlenmiştir. Optik mikroskop kullanılarak deney malzemelerinin aşınma yüzeyi incelenmiştir. Deneyler sonucunda kayma hızına bağlı olarak hem saf PEEK hem de karbon elyaf takviyeli PEEK kompozitin sürtünme katsayısı azalırken aşınma oranı artış göstermiştir. Karbon elyaf takviyeli PEEK kompozitin saf PEEK polimerine göre ortalama %50 oranında daha yüksek aşınma direncine sahip olduğu tespit edilmiştir.

Development of a CFD-based model to simulate loss of flow transients in a small lead-cooled reactor

With the deployment of advanced and small modular reactors (SMRs), it is important to develop the tools to assess their safety. This work presents the different components of a CFD based model for simulating transients in a pool-type small lead cooled reactor. The model encompasses the entire primary circuit with a simplification of the fuel channels, pumps and steam generators. Those parts are modelled through heat and momentum sources (or sinks), similar to the porous medium used in other studies. The CFD solver is coupled with a finite volume solver for fuel pin temperature and a point kinetics solver for neutronics. Free surface is modelled in CFD with multiphase volume of fluid method. The set of methods that is used in this work constitute a novelty for modelling lead cooled reactors. The goal is to have a model that is relatively simple to implement in order to study the effect of some parameters on reactor transients like an unprotected loss of flow. The focus of this study is to describe in detail every individual component of the model, namely the fuel channels, fuel pin temperature, neutronics, coupling strategy, pump and steam generators. In addition, CFD simulations are compared against experimental data from the TALL-3D facility. The purpose of this comparison is to verify that the models and parameters of the CFD software (STAR-CCM+) are capable of reproducing a flow of heavy metal. A future publication will provide the simulation results of an integrated model with all the components.

Wear behaviour of C/C–SiC composites sliding against high-Cr steel discs

Abstract An experimental investigation was conducted to examine the wear behaviour of cross-ply carbon– carbon – silicon carbide composites (C/CαSiC) under dry sliding against a chromium steel disc at various speeds and loads. Results indicated that under identical conditions, C/C– SiC composites with weak fibre resin interfaces at all times had a larger weight loss than those with a strong bond. In the first few minutes of wear, weight losses were approximately the same for both types of composites. Also, the wear rates of both the composites decreased sharply with sliding distance up to 7 km, and then gradually tended to become constant. Scanning electron microscopy showed that the graphite film was transferred on the test pin side, which stabilizes the increase in test pin temperature after the formation of a thick film of graphite debris.

CFD analysis of a solid pin-fueled small modular fluoride salt-cooled reactor

A computational fluid dynamics (CFD) study is performed for the pre-conceptual solid pin-fueled small modular fluoride salt-cooled reactor developed by the Oak Ridge National Laboratory (ORNL). The solid and fluid regions in a 1/12th section of a fuel assembly are modeled. The solid region includes fuel and non-fuel pins, with heat generation in the active region of the fuel pins. Two different power profiles, uniform and center-peaked, are considered. The FLiBe coolant flows from the bottom to the top of the core, parallel to the bank of fuel and non-fuel pins. The k-ω shear-stress transport (SST) model is chosen as the baseline turbulence model. The effects of grid refinement, inlet turbulence specification, and turbulence models on the temperature and pressure drop predictions are studied. Turbulence model sensitivity is investigated by comparing the results from the k-ω SST model with other two-equation models (k-ω baseline or BSL and k-ε realizable) as well as with anisotropic Reynolds stress transport models (linear pressure-strain and stress-BSL). The results show that the choice of turbulence model has a significant impact on the pin temperature and bundle pressure drop predictions. The results from the baseline turbulence model show good agreement between the fuel pin temperatures and bundle pressure drop values predicted using a subchannel model previously developed by the authors of the present study.

Optimization of dry sliding wear characteristics of Al–25Zn/SiC hybrid composites by graphite reinforcement using artificial neural network and Taguchi’s method

ABSTRACT This paper proposes a unique Al25Zn/SiC/Graphite hybrid composite for plain bearing and other wear-resistant applications. Newly synthesized composites of Al–25Zn alloy reinforced with 3 wt-% graphite and 10, 15 and 20 wt-% SiC are tested using a pin on the disc tribometer following ASTM G-99 standard against EN24 disc. Sliding wear studies using the Taguchi L16 array are carried out for a set of parameters including pin temperature, speed, load and a constant sliding distance. The results reveal that adding 3 wt-% graphite into Al25Zn/SiC composites greatly enhances wear resistance, tensile strength, impact strength and ductility at the expense of hardness. The wear behaviour of the composites is predicted using an artificial neural network and a regression model. Adhesion is found the most common wear mechanism in matrix alloys, while abrasion and delamination in composites. Among the examined materials, the composite with 3 wt-% graphite and 15 wt-% SiC has the optimum combination of characteristics.

Ex Situ Tribological and Electro-chemical analysis of Aluminium

Aluminium sample coupon is evaluated for electro-chemical, tribological and microstructural study under selected test conditions. Aluminium is a light-weight material chiefly preferred in fields like automobile, aerospace, marine and satellite domestic appliances etc. Moreover, due to its specific characteristics, it plays a crucial role in industries and research fields. In the present work, the ex situ tribological (wear test), electrochemical (corrosion test), mechanical (microhardness test) and microstructural (nodularity percentage) behaviours of Aluminum sample is presaged. The test results reveal that, when experiment advance, with respect to time the wear rate increases, frictional force is decreased and pin temperature increased. The corrosion test is held on specimen coupon in two modes, before and after wear test, and observed that the corrosion rate gets improved on specimen after wear test. Nodularity analysis also express that the nodularity percentage is increased by 5%. Before wear test, the percentage of accepted count to total count of nodules on texture is 65.18%, while the percentage after wear test is found to be 70.29%. The Vickers Microhardness analysis exhibits the hardness value as 160 HV on Vickers Hardness Scale.

Grey relational analysis for optimization of wear parameters and surface roughness on nano composite coating

The higher wear resistance of Ni based nano composite coatings makes them potential replacement in protecting the substrate materials. The role of surface roughness of the coating along with wear parameters on the specific wear rate, pin temperature, and COF are addressed in the present study. The use of hard nano Al2O3 particles found significant role in increasing the resistance to wear for Ni matrix coatings on Al6061 material. The resistance to dislocation offered by these nano Al2O3 particles and smear out of debris with plastic deformation indicated abrasive and adhesive nature of wear mechanism in combination. The optimization of wear parameters are carried out by surface response method based grey relation analysis. The normal load applied onto the pin has significant influence on the specific wear rate and temperature rise in the pin. The surface roughness of the coating has also found instrumental in the higher pin temperature and friction coefficient.

Statistical and artificial neural network technique for prediction of performance in AlSi10Mg-MWCNT based composite materials

The present research paper deals with AlSi10Mg alloy/MWCNT metal matrix composite brake pads with varying weight percentages. The Development of new brake pad materials has been done at compacting load (10 Tons) and sintering temperature (450 °C) using the powder metallurgy process. The input parameters of 40 N normal load, 500 rpm, 150 °C pin temperature as the near-optimal combination of parameters for minimum wear and maximum coefficient of friction compared to other test conditions have been observed by the design of experiment (DOE). The overall average percentage error in the output against experiment output is less than 1%. Analysis of variance (ANOVA) indicates that load is a most significant factor than speed and temperature for wear and CoF. Artificial Neural Network (ANN) is used to develop a prediction model to calculate wear and coefficient of friction for different loads, pin heating temperature and speed. The model developed shows a strong correlation with experimental output. The experimental and predictive model developed from artificial neural network are strongly correlated with a correlation factor of 0.99447 for the training algorithm of Levenberg-Marquardt technique. ANN prediction model and Taguchi L16 array reveal that the experimental and predicted data for mass loss and CoF have less than 3% and 4% error, respectively. The closeness between the artificial neural network and experiment results enhances the scope of ANN for predicting the wear of materials. The model will help engineers to predict the failure of components with reference to running time and can be applied in automobile or manufacturing sectors to study wear, thus saving their time and cost in carrying out experiments.

Hot and average fuel sub-channel thermal hydraulic study in a generation III+ IPWR based on neutronic simulation

The Integral Pressurized Water Reactors (IPWRs) as the innovative advanced and generation-III + reactors are under study and developments in a lot of countries. This paper is aimed at the thermal hydraulic study of the hot and average fuel sub-channel in a Generation III + IPWR by loose external coupling to the neutronic simulation. The power produced in fuel pins is calculated by the neutronic simulation via MCNPX2.6 then fuel and coolant temperature changes along fuel sub-channels evaluated by computational fluid dynamic thermal hydraulic calculation through an iterative coupling. The relative power densities along the fuel pin in hot and average fuel sub-channel are calculated in sixteen equal divisions. The highest centerline temperature of the hottest and the average fuel pin are calculated as 633 K (359.85 °C) and 596 K (322.85 °C), respectively. The coolant enters the sub-channel with a temperature of 557.15 K (284 °C) and leaves the hot sub-channel and the average sub-channel with a temperature of 596 K (322.85 °C) and 579 K (305.85 °C), respectively.It is shown that the spacer grids result in the enhancement of turbulence kinetic energy, convection heat transfer coefficient along the fuel sub-channels so that there is an increase in heat transfer coefficient about 40%. The local fuel pin temperature reduction in the place and downstream the space grids due to heat transfer coefficient enhancement is depicted via a graph through six iterations of neutronic and thermal hydraulic coupling calculations. Working in a low fuel temperature and keeping a significant gap below the melting point of fuel, make the IPWR as a safe type of generation –III + nuclear reactor.

Study on Wear Mechanism and Contact Temperature against Dry Sliding Wear of Ni-Al2O3 Nanocomposite Coating

ABSTRACT Dry sliding wear experiments were carried out at constant normal load and sliding speed on electrodeposited Ni and Ni-α-nano Al2O3 coatings. The coating surfaces were worn against EN-32 HRc hardened steel in pin-on-disc test rig. The work was concentrated on the pin temperature, frictional force and specific wear rate of the coating which were measured as the function of sliding distance. The Ni coating was reported with lower frictional force and pin temperature in comparison with Ni-Al2O3 composite coating. Specific wear rate of the coating with nanoparticles was found to be lower than that of without particles in the Ni matrix. Pure abrasive nature of wear was reported for Ni-Al2O3 composite coating. This resulted in higher pin temperature for the composite coating with nanoparticles. The lower specific wear rate of Ni-Al2O3 is attributed to the hard nature of nanoparticles and resistance to thermal plastic deformation by the coating. Characterization of the coating was carried out by SEM, EDS, XRD analysis.

Wear behavior and pin temperature of Ni-Al2O3 nano composite coating by electro co-deposition process

The Al6061 substrate is used as the substrate material due its vast applications in the field of automobile and aeronautics. The Ni composite coating with Al2O3 nano particles has shown significant improvement in reducing specific wear rate. This also helps in the rise of pin temperature which is resulted from during wear under dry conditions. The response surface methodology (RSM) is used to design the experiments for the study of different wear parameters. Wear behaviour and rise in pin temperature for different 20 numbers of combinations of wear parameters is found out. The specific wear rate and rise in pin temperature are greatly influenced by the normal load applied on the samples.

EXPERIMENTAL INVESTIGATION OF DRY SLIDING WEAR BEHAVIOUR OF STIR CASTED AZ31 MAGNESIUM ALLOY-CASIO3 METAL MATRIX COMPOSITES

Metal matrix composites (MMCs) became one of the obligatory material in the transportation sector where Magnesium MMCs are in high demand due to their exclusive properties like low density, good wieldable, recyclable, and casting. In the present work, wear behavior of AZ31 magnesium alloy added by calcium silicate (CaSiO3) as additive of various compositions of its weight percentage from 0 to 8% is determined and tested under dry sliding condition. After experimentation, results revealed that the sample S-3 which comprises 4% CaSiO3, shows the minimum pin temperature of 33.1 0C. In terms of frictional force, sample S-4 which has 6% CaSiO3, shows a least frictional force of 4.81 N. The sample S-2 formed by 2% CaSiO3 shows the highest value of 14.1 N of frictional force. By comparing the coefficient of friction value, the specimen sample S-4 displays the least friction value of 0.160 µ and sample S-2 exhibits the highest value as 0.470 µ. Wear occurred between pin and disc is observed as 292 µm for sample S-2 which is low compared to sample S-4 of 324 µm. By consolidation of results, the sample S-4 shows better performance in terms of force, coefficient of friction, and pin temperature concerning time.

Influence of Pin Temperature on Dry Sliding Wear Behaviour of Ni–Al2O3 Composite Coating on Al6061 Substrate

The lightweight materials like aluminium is used in most of the automobile, aeronautical applications due to its high strength to weight ratio. In the present study, high-temperature wear behaviour of Al6061 substrate material with Ni–Al2O3 nanocomposite coating at different elevated temperatures is studied. The tests were conducted at dry sliding wear conditions. The coating was carried out by electrodeposition process. In addition to high-temperature specific wear, hardness of the glaze layer and friction force of composite coating are investigated. The results reveal that the dominant wear mechanism of the Ni–Al2O3 coating was in abrasive nature at 40 °C which turned into completely adhesive nature at elevated temperatures between 80 and 140 °C. The minimum mild wear with reduced frictional force was noticed at 80 °C due to the formation of glaze layer. This anti-wear resistance glaze layer is formed by the sintering of debris and oxide particles at the interface of pin and disc. At 140 °C, severe wear with serious plastic deformation was observed. The improvement in the specific wear is attributed by the presence of nano-Al2O3 particles in the Ni matrix and wear resistant glaze layer. This was witnessed by the microstructure observations by SEM, EDS, and microhardness measurements.