Corrigendum: Numerical analysis of flow and heat transfer in a thin film along an unsteady stretching cylinder

Name of the 5th author Hijaz Ahma is not written correctly, by technical error. Correct name of the 5th author has to be written as Hijaz Ahmad. <br><br><font color="red"><b> Link to the corrected article <u><a href="http://dx.doi.org/10.2298/TSCI21S2441S">10.2298/TSCI21S2441S</a></b></u>

Effect of sic particles on viscosity of 3d print paste: A fractal rheological model and experimental verification

This paper studies the effect of the rheological property of SiC-based print paste on the 3D printability at different SiC concentrations. The viscosity depends both the size and concentration of the added particles, a fractal rheological model is suggested and verified experimentally.

Heat transfer in a novel microwave heating device coupled with atomization feeding

The heat transfer characteristics of the microwave heating coupled with atomization feeding were investigated using ethanol as the spray medium on a pressure swirl nozzle. The effects of spray height, flow rate and temperature on the sauter mean diameter (SMD) of atomized droplets were examined. The results showed that the droplet SMD was 12-130 ?m, which increased with the spray height and decreased with the flow rate and temperature of spray medium. Through the fitting of the experimental data, the dimensionless correlation of the droplet SMD which was based on orifice diameter, Reynolds and Ohnesorge numbers was obtained. The calculated results were basically consistent with the experimental data within 15% error. The heat transfer characteristics of atomized droplets on high-temperature surface of SiC bed heated by microwave were then investigated. The effects of spray flow rate, spray height and spray temperature on the heat transfer characteristics were examined. The power of spray heat transfer decreased with the temperature and increased with the spray flow rate and spray height. The dimensionless correlation to describe the heat transfer characteristics of atomized droplets on the high-temperature SiC surface under the microwave heating was obtained which included thermophysical properties of spray medium, spray parameters, and temperatures of the high-temperature bed surface and spray medium, with the error of ?20%. These correlations can be used to predict the SMD of the atomized droplets and the power of spray heat transfer in the microwave heating process.

High-resolution simulation of film cooling with blowing ratio and inclination angle effects based on hybrid thermal lattice Boltzmann method

A series of high-resolution simulations on film cooling with varying blowing ratios and inclination angles are carried out by using in-house code based on hybrid thermal lattice Boltzmann method. Three blowing ratios ranging from 0.2 to 0.8 and four inclination angles from 15? to 60? are chosen for the simulations. The evolutionary mechanism of coherent structure in three domains of film-covering region is studied from the view of space and time. Besides, the influencing mechanism of blowing ratio and inclination angle on flow and heat-transfer features of film cooling is uncovered. Results show that hairpin vortex, hairpin packet and quasi-stream-wise vortex appearing in rotating domain play a key role in heat-transfer process of film cooling. The strong ejection, sweep and vortex rotation resulted from these vortices enhance the convective heat transfer. It is also found that the size of coherent structure varies significantly with blowing ratio and its integral form shows a strong dependence on inclination angle. Moreover, inclination angle of coolant jet has a significant impact on turbulence fluctuation intensity. The influence of blowing ratio on the attachment of coolant film and film-cooling performance is more obvious than that of inclination angle. It is believed that all of these are related closely to the variation of stream-wise and wall-normal jet velocity in the case of various blowing ratios and inclination angles.

Optimization and application of temperature field in rapid heat cycling molding

The rapid thermal cycle molding (RHCM) belongs to the injection mold temperature control system which is helpful to improve mold ability and enhance part quality. Despite many available literatures, RHCM does not represent a well-developed area of practice. The challenge is the uneven distribution of temperature in the cavity after heating, which mostly leads to defects on the surface of the products. In order to obtain uniform cavity surface temperature distribution of RHCM, the power of heating rods of the electric-heating system in an injection mold was optimized by the response surface method(RSM) in this work. The proposed optimization result was applied to design a complex RHCM injection mold with side core-pulling, holes and different thickness of an automotive part to verify its effectiveness by injection molding. Compared with initial design, the mold temperature uniformity was remarkably improvedby79%. Based on the optimization and injection molding numerical simulation results, the workable molding process to weaken the weld-lines effects on the quality was suggested and the practical injection molded parts were well produced.

Metallic plate heating by a flat burner: Experiments and CFD simulations

Metal plate heating by new microflare burner has been studied experimentally and by CFD simulations, additionally, concentrations of NOx were measured to compare conventional and microflare burners. In addition, the article provides a numerical simulation of the combustion of a microflame burner. It has been demonstrated that microflare burners are more efficient and allows more uniform heating of metal plates. The comparison of NOx concentrations of conventional and microflare burners indicate better performance of the latter.

Thermal optimization research of oil-immersed transformer winding based on the support machine response surface

In this paper, the CFD (computational fluid dynamics) model is established for the low voltage winding region of an oil-immersed transformer according to the design parameters, and the detailed temperature distribution within the region is obtained by numerical simulation. On this basis, the RSM (response surface methodology) is adopted to optimize the structure parameters with the purpose of minimizing the hot spot temperature. After a sequence of designed experiments, the second-order polynomial response surface and the SVM (support vector machine) response surface are established respectively. The analysis of their errors shows that the SVM response surface can be better used to fit the approximation. Finally, the PSO (particle swarm optimization) algorithm is employed to get the optimal structure parameters of the winding based on the SVM response surface. The results show that the optimization method can significantly reduce the hot spot temperature of the winding, which provides a guiding direction for the optimal design of the winding structure of transformers.

Corrigendum: Thermodynamic performance of ammonia in liquefied natural gas precooling cycle

Simeon Oka, Editor-in-Chief Emeritus of the journal Thermal Science request that it is necessary write correction in Table 6, p. 2012, in the paper THERMODYNAMIC PERFORMANCE OF AMMONIA IN LIQUEFIED NATURAL GAS PRECOOLING CYCLE by Ray SOUJOUDI

Effect of surface micromorphology and hydrophobicity on condensation efficiency of droplets using the lattice Boltzmann method

In the present study, the effects of the surface morphology and surface hydrophobicity on droplet dynamics and condensation efficiency are investigated using the lattice Boltzmann method (LBM). Different surface morphologies may have different condensation heat transfer efficiencies, resulting in diverse condensation rates under the same conditions. The obtained results show that among the studied morphologies, the highest condensation rate can be achieved for conical microstructures followed by the triangle microstructure, and the columnar microstructure has the lowest condensation rate. Moreover, it is found that when the surface microstructure spacing is smaller and the surface microstructure is denser, the condensation heat transfer between the surface structure and water vapor facilitates, thereby increasing the condensation efficiency of droplets. Furthermore, the condensation process of droplets is associated with the surface hydrophobicity. The more hydrophobic the surface, the more difficult the condensation heat transfer and the longer the required time for droplet nucleation. Meanwhile, a more hydrophobic surface means that it is harder for droplets to gather and merge, and the corresponding droplet condensation rate is also lower.

Analysis of the multiphase lubricating oil effect on the performance of the tilting-pad journal bearing

As heavy industry develops, large amounts of tilting-pad journal bearings are widely used in advanced technology and key equipment. So, it has become a hot research direction to ensure the stable operation of tilting-pad journal bearings by using multiphase lubricating oil. The aim of the present research was to clarify whether using the multiphase lubricating oil has a positive effect on the performance of the bearings. The approach is based on computational multiphase fluid dynamics and finite-element method. Reynolds averaged equations of multiphase flow was applied to computation for improving the accuracy. The change of loading capacity of oil film was studied with computational fluid dynamics simulation under particles added to the lubricating oil. The results indicate that the bearing capacity of bearing increases when the particle content, diameter and density increase. The performance of bearing becomes better when the multiphase lubricating oil is applied in the oil film of bearing. The implications of these results are that the development of multiphase lubricating oil has important practical significances.