Numerical Simulation of Infiltration of Carbon Fiber Preform in MMC Casting With Thermal Management

2003 ◽  
Author(s):  
E. K. Lee ◽  
R. S. Amano ◽  
P. K. Rohatgi
Keyword(s):  
Numerical Simulation ◽  
Thermal Management ◽  
Heat Sink ◽  
Volume Fraction ◽  
Solidification Process ◽  
Mold Temperature ◽  
Processing Parameters ◽  
Companion Paper ◽  
Heat Extraction ◽  
Squeeze Infiltration

In the casting of metal matrix composite, different processing parameters need to be controlled in order to promote the formation of primary alpha phase around the reinforcement. It has been shown [1–3] that when the reinforcement is allowed to be extended out of the cast mold and cooled by a heat sink, the microstructure of the composite can be improved due to faster heat extraction through the reinforcement. Thermal management of the reinforcement can eliminate a large portion of the eutectic phase during solidification, leading to an altered microstructure at the interface between the matrix and the reinforcement with the possibility of improved material properties. A companion paper [4] shows a comparison of the numerical simulation result of the casting of MMC by squeeze infiltration technique to the experimental work. The authors assumed that the solidification process started after the liquid metal has completely infiltrated the reinforcement. The simulation result gives a reasonable prediction to the experimentally measured cooling temperature profile. In this work, the effects of other processing parameters are analyzed to study the impregnation depth during squeeze infiltration. These processing parameters include the thermal conductivity of fibers, the initial (or preheat) mold temperature, the volume fraction of fibers, and the heat sink temperature. The study is based on the finite volume method for enthalpy formulated heat equation.

Study on one Dimensional Numerical Simulation in Filling Stage of Water-Assisted Injection Molding

2011 ◽  
Vol 179-180 ◽  
pp. 1193-1198 ◽  
Author(s):  
Tang Qing Kuang
Keyword(s):  
Numerical Simulation ◽  
Injection Molding ◽  
Water Temperature ◽  
Water Pressure ◽  
Mold Temperature ◽  
Processing Parameters ◽  
Melt Temperature ◽  
Filling Stage ◽  
Short Shot ◽  
Temperature Water

Water assisted injection molding is a pretty novel way to fabricate hollow or more complicated parts. Its molding window and process control are more critical and difficult since additional processing parameters are involved. A simulation model for the filling stage of a pipe cavity during short-shot water assisted injection molding was proposed. The finite element/finite difference/control volume methods were adopted for the numerical simulation. A numerical study, based on the single factor method, was conducted to characterize the effect of different processing parameters on the short shot water-assisted injection-molding of thermoplastic composites, including short-shot size, melt temperature, mold temperature, water temperature and water pressure. For the factors selected in the simulations, short-shot size was found to be the principal parameters affecting the water penetration length while melt temperature, mold temperature, water temperature, water pressure were found to have little effect on the penetration of water.

A Parametric Study on the Infiltration of Fibrous Preform by Pure Al and Solidification Process in the Presence of Cooled Fibers

2003 ◽  
Author(s):  
E. K. Lee ◽  
R. S. Amano ◽  
P. K. Rohatgi
Keyword(s):  
Heat Sink ◽  
Initial Temperature ◽  
Pure Aluminum ◽  
Liquid Aluminum ◽  
Solidification Process ◽  
Processing Parameters ◽  
Pure Liquid ◽  
Infiltration Process ◽  
Injection Process ◽  
Heat Sink Temperature

Numerical simulation of the injection process of pure liquid aluminum into a fibrous preform has been carried out. During the injection process the end of the fibrous preform is allowed to be cooled by a heat sink. The purpose of cooling by a heat sink is to achieve a higher cooling rate, which is essential in obtaining finer microstructures and enhancing the growth of aluminum dendrites. The injection of liquid aluminum is modeled as flow in a porous medium and the heat equation coupled with the Darcy’s equation are simultaneously solved to obtain the temperature and velocity field. There are many different processing parameters influencing the solidification of aluminum. Among these parameters are, but are not limited to, the heat sink temperature, the thermal conductivity and initial temperature of the mold, and the length of fiber that is extending out of the mold. This article presents the simulation results of the effects of these processing parameters on the solidification of pure aluminum during the infiltration process.

Transport Phenomena During Solidification Processing of Functionally Graded Composites by Sedimentation

2000 ◽  
Vol 123 (2) ◽  
pp. 368-375 ◽  
Author(s):  
J. W. Gao ◽  
C. Y. Wang
Keyword(s):  
Volume Fraction ◽  
Pure Water ◽  
Particle Volume Fraction ◽  
Solidification Process ◽  
Processing Parameters ◽  
Functionally Graded ◽  
Particle Volume ◽  
Solidification Model ◽  
Free Zone ◽  
Free Region

A combined experimental and numerical investigation of the solidification process during gravity casting of functionally graded materials (FGMs) is conducted. Focus is placed on understanding the interplay between the freezing front dynamics and particle transport during solidification. Transparent model experiments were performed in a rectangular ingot using pure water and succinonitrile (SCN) as the matrix and glass beads as the particle phase. The time evolutions of local particle volume fractions were measured in situ by bifurcated fiber optical probes working in the reflection mode. The effects of important processing parameters were explored. It is found that there exists a particle-free zone in the top portion of the solidified ingot, followed by a graded particle distribution region towards the bottom. Higher superheat results in slower solidification and hence a thicker particle-free zone and a higher particle concentration near the bottom. The higher initial particle volume fraction leads to a thinner particle-free region. Lower cooling temperatures suppress particle settling. A one-dimensional multiphase solidification model was also developed, and the model equations were solved numerically using a fixed-grid, finite-volume method. The model was then validated against the experimental results and subsequently used as a tool for efficient computational prototyping of an Al/SiC FGM.

Numerical Simulation of Shrinkage in the Microinjection Molding of Multi-Microparts Produced in one Mold

2011 ◽  
Vol 221 ◽  
pp. 649-656 ◽  
Author(s):  
Jian Wang ◽  
Wei Min Yang
Keyword(s):  
Numerical Simulation ◽  
Injection Molding ◽  
Plastic Material ◽  
Control Volume ◽  
Injection Pressure ◽  
Mold Temperature ◽  
Processing Parameters ◽  
Injection Molding Process ◽  
Melt Temperature ◽  
Microinjection Molding

The aim of this paper is to verify the reliability of numerical results obtained by using MPI (Moldflow Plastic Insight) for predicting the shrinkage of multi-microparts produced in one mold in microinjection molding. 3D numerical simulation (control volume finite element method) was employed. Pure and 10-20 % GRF (glass fiber reinforced) POM materials were used for the plastic material. The injection molding process was used for different parameters (mold temperature, melt temperature and injection pressure). A DOE (Design of Experiments) technique was then used to plan the numerical simulation activity of the injection molding phase. Among injection processing parameters (mold temperature, melt temperature and injection pressure), the results showed that the mold temperature is the most important factor to affect the shrinkage of multi-microparts significantly for processing parameters. The results also indicated that the processing is very well for micro-injection molding by numerical simulation. In addition, properties of polymer composites with added fillers were systematically studied. Numerical simulation results showed that the numerical resulting composites with 10–20 wt% glass particles exhibited significant improvement in shrinkage, and showed good agreement with experimental results.

scholarly journals Numerical Simulation of Heat Transfer during Solidification of Al–Cu Alloy Ingots Cast in a Cylindrical Mold for Different Conditions

2016 ◽  
Vol 13 (1) ◽  
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Mold Wall ◽  
Solidification Process ◽  
Mold Temperature ◽  
Outer Radius ◽  
Cu Alloy ◽  
First Case ◽  
Cylindrical Mold ◽  
Alloy Cast

In this paper, two dimensional numerical simulation of heat transfer during solidification of Al- 4.5 wt. % Cu alloy cast in a cylindrical mold was carried out to specify the optimum solidification conditions. The mold has the dimensions of 150 mm height, 38 mm outer radius, and 8 mm thickness. Four cases were studied for the solidification process; first case is the solidification in the mold without applying any thermal effects at four different mold temperatures of 25, 50, 100 and 200 Ԩ respectively. The second case is insulating the cast from the top. The third case is insulating the upper portion of the mold wall. The last case is adding heat to the upper portion of the mold wall for specific time. For the last three cases, the mold temperature is set to 25Ԩ. The results have shown that the increase in mold temperature only increases the solidification time and it does not significantly affect the temperature distribution and the final cast shape. Insulating the top of the mold made the last solidification region to be at the top of the cast, which leads to get ingot free from the secondary cavity. Insulating a portion of the upper wall of the mold made the cast surface to be more homogeneous with smallest secondary cavity. Heat addition to a portion of the upper wall of the mold leads to obtain a cast with approximately flat surface that is free from secondary cavity in addition to the primary cavity.

scholarly journals Numerical Analysis of Thermal Management for High Power LED Array

2021 ◽  
Vol 257 ◽  
pp. 01033
Author(s):  
Yingdong Shen ◽  
Junfeng Dai ◽  
Yanlong Wang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Exchanger ◽  
Thermal Management ◽  
Heat Sink ◽  
Junction Temperature ◽  
Manufacturing Cost ◽  
Specific Work ◽  
Safe Operation ◽  
Led Array

Adequate thermal management to remove and dissipate the heat produced by the LED is one of the main challenges in designing LED applications. In view of the above problems, this paper analyzed a heat sink as a heat exchanger for the LED array via the experiment combined with the numerical simulation. The results show that the heat sink is necessary for the LED array to guarantee reliable and safe operation. Moreover, the influence of the height of heat sink on the heat transfer of the LED array is also analyzed, and the optimized height of the heat sink for the 20W LED array is 20 mm. Considering the heat transfer and the manufacturing cost, increasing the heat sink area blindly is not the best way to reduce the LED junction temperature, and more specific work should be considered.

On the Numerical Analysis of Different Controlling Parameters During the Solidification of Aluminum-Carbon Fiber Composite With Thermal Management

2002 ◽  
Author(s):  
R. S. Amano ◽  
E. K. Lee ◽  
P. K. Rohatgi ◽  
H. G. Seong ◽  
V. K. Tiwari
Keyword(s):  
Heat Sink ◽  
Volume Fraction ◽  
Fiber Composite ◽  
Axial Direction ◽  
Metallic Phase ◽  
Solidification Time ◽  
Heat Extraction ◽  
Symmetric Model ◽  
Carbon Fiber Composite ◽  
Calculation Domain

Metal matrix composites (MMCs) consist of two or more distinct phases, namely a continuous metallic phase known as the matrix and a reinforcing phase. MMCs offer advantages over traditional monolithic materials of enhanced material properties such as strength, thermal/electrical conductivity, toughness, modulus of elasticity, wear resistance, etc. It is desirable to shorten the solidification time when producing MMCs because the higher the cooling rate, the finer the microstructures of the MMCs will be. The present research investigates MMCs processed in a novel way, in which the ends of the reinforcement phase are extended outside the liquid matrix envelope and cooled by a heat sink. By doing so, heat extraction in the axial direction greatly reduces the solidification time compared with conventional way of making MMCs. Due to the complicated geometry of the calculation domain, analytical result is very difficult to obtain. Therefore, attempts have been made to solve the energy equation by finite difference numerical method for a 2-D axis-symmetric model involving phase change. The calculation domain is based on the proposed experimental configuration by Rohatgi et al. [1]. In this paper, the effects of selected parameters which can influence the process of solidification are examined. These parameters include the volume fraction, the thermal conductivity of the reinforcing phase, and the heat sink temperature.

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