In the present study a finite difference method has been developed to model transient fluid flow and heat transfer in metal casting. A single fluid has been selected for modeling the mold filling and the SOLA VOF 3D technique was modified to increase the accuracy and speed of simulation of filling phenomena for shape castings. The model was then evaluated with the experimental methods. Referring to the experimental and simulation results, a good consistency and accuracy of the suggested model are observed.

In this research, the zeolitic imidazolate framework 67 (ZIF-67) and carboxymethyl cellulose (CMC)/ZIF-67 biocomposite (CMC/ZIF-67) were synthesized. Different analyses were used to characterize the synthesized materials. Then, carboxymethyl cellulose and CMC/ZIF-67 biocomposite were used to remove the dye (Malachite Green: MG). The results showed that the dye removal capability of biocomposite (92.35%) is higher than that of carboxymethyl cellulose polymer (9.41%). As the adsorbent dose increases, the removal percentage of MG also increases. As the adsorbent dose increases, the active sites of the adsorbent surface are more accessible, and the dye removal percentage is higher. The dye removal percentage in 1, 2, 3, and 4 mg of composite adsorbent was 25, 54, 79, and 92.35%, respectively. With the increase in dye concentration, the amount of dye removal decreased. The dye removal in 20, 30, 40, and 50 mg/L concentrations with composite was 92.35, 85, 79 and 71%, respectively. The presence of imidazole rings in the structure of ZIF-67 as a ligand can be one of the main reasons for the high adsorption capacity of the biocomposite. Due to the double bonds in the imidazole rings, Π-Π stacking interactions occur with the aromatic rings of MG. This special interaction enables the biocomposite to adsorb the high capacity of MG. The isotherm and kinetics of dye adsorption by CMC/ZIF-67 biocomposite followed the Langmuir isotherm and pseudo-second-order kinetics.  

During solidification and casting in metallic molds, the heat flow is controlled by the thermal resistance at the casting-mold interface. Thus heat transfer coefficient at the metal- mold interface has a predominant effect on the rate of heat transfer. In some processes such as low pressure and die-casting, the effect of pressure on molten metal will affect the rate of heat transfer at least at initial steps of solidification. In this study interfacial heat transfer coefficient at the interface between A356 alloy casting and metallic mold during the solidification of casting under pressure were obtained using the IHCP (Inverse Heat Conduction Problem) method. Temperature measurements are then conducted with the thermocouples aligned in the casting and the metallic mold. The temperature files were used in a finite-difference heat flow program to estimate the transient heat transfer coefficients. The peak values of heat transfer coefficient obtained for no pressure application of A356 alloy is 2923 (w/m2k) and for pressure application is 3345 (w/m2k). Empirical equation, relating the interfacial heat transfer coefficient the applied pressure were also derived and presented.

Shorter cycle times, better product quality and less product outage can be possible with faster cooling. But mold cooling channels can only be made in linear directions and limited forms via classical manufacturing methods. Therefore, it limits that performance of mold cooling. Developed in recent years additive manufacturing technologies are capable of building complex geometries and monoblock 3D products. With this technology it is possible to produce metal molds with conformal cooling channels in different forms and capable of qualified cooling. In this study, conformal cooling channels were designed in order to achieve optimum cooling in monoblock permanent mold. In this study, CFD (Computational Fluid Dynamic) analyses are performed to steady stead conditions for designed conformal cooling channels and classical cooling channel mold. Pressure drops, cooling channel outlet temperatures and exergy destructions are calculated depending on the flow velocity rate in channels. The numerical investigations of the cooling process have shown that approximately 5% higher cooling performance can be achieved with conformal cooling channels. However, the pressure drop in the conformal cooling is observed to be higher than classical cooling channel. In addition, exergy destruction in the conformal cooling channel is approximately 12% greater than the classical cooling channel.

The most important steps in the metal injection molding (MIM) process are the design and manufacture of the injection mold. By far the most influential factors in the quality of the part are the injection site in the mold and how the part is filled during the injection molding, which directly affects the quality of the final part. In this paper, a powder containing 316L stainless steel is used as the raw material, and the Moldex 3D software is used for the simulations. The injection time, the cooling time, and the keeping time parameters are considered fixed for all tests with the values of 2. 5, 10, and 2 seconds respectively. The speed, pressure, and temperature of injection are also considered as effective parameters. The boundary layer method (BLM) is used to simulate the process. The 3D model of the part is designed with three gate paths and different injection conditions. The injection mold is made for the optimized sample and produced under different conditions. Comparing the results of simulations with the experimental results shows the accuracy of the simulation results. The results also show that in the process of MIM, the injection fluid has a very high viscosity and different behavior compared to the similar fluid of the base polymer used in the feed. Besides, the optimal values for speed, pressure, and temperature of injection are found to be 60%, 60%, and 185 °,C, respectively.

In this paper, a transient, two-dimensional and nonlinear inverse heat conduction problem in solidification process is considered. Genetic algorithm is applied for the identification of the interfacial heat transfer coefficients during squeeze casting of commercial aluminum alloy (Al-4.5wt%Cu) by assuming a priori information regarding the functional form of the unknown heat transfer coefficients found in open literature. In this work, simulated (noisy and filtered) temperatures are used instead of experimental data. The estimated temperatures are obtained from the direct numerical solution of a two-dimensional conductive model. A modified elitist genetic algorithm is used to minimize the least square objective function containing estimated and simulated temperatures. The accuracy of the proposed method is assessed by comparing the estimated with the pre-selected parameters.

The cooling process in metal molds is one of the important factors in the solidification process of molten metal. Molding defects such as hot spot defects and warping occur in cast products when the cooling is not uniform. However, qualified and faster cooling affects product quality positively. Molding is one of the important processes both in terms of cycle time and product quality, with permanent mold casting, high quality liquid metal casting, and quality product. Selective Laser Melting (SLM) method has been used to design metal mold cores with unique cooling channels to be compactly produced. The effects of the designed cooling channels, heat transfer and solidification of the molten metal are studied in transient numerical terms. The temperature distributions for 1, 3 and 5 seconds after casting were obtained and the solidification processes were investigated according to the standard cooling channels of the original cooling channels. According to the results obtained, it has been observed that solidification is better in originally designed cooling channels.