Effective Modeling of Phenomena in Over-Moisture Zone Existing in Porous Sand Mould Using the Simplified Simulation Systems Applied in Foundry

2015 ◽  
Vol 365 ◽  
pp. 200-206
Author(s):  
Zenon Ignaszak ◽  
Paweł Popielarski
Keyword(s):  
Physical Properties ◽  
Temperature Fields ◽  
Mould Material ◽  
Technological Tool ◽  
Sand Mould ◽  
Thermal Phenomena ◽  
Simulation Systems ◽  
Thermo Physical Properties ◽  
Auxiliary Role

The problem concerns the thermo-physical properties of the mould material to which the liquid metal is poured (foundry industry). In the foundry processes the sand mould fulfils an auxiliary role only as technological tool, but its physical and technological properties determine the quality of the casting. The study includes the iron plate casting experiments poured in multi-component porous sand mould. The temperature fields of casting and in different zones of the mould were recorded. The determining of the thermo-physical properties of mould sand in over-moisture zone using simulation tests in Procast system was the goal of our study. An originality of the related research is an attempt to take into account the effects of the global thermal phenomena occurring in the quartz sand bonded by bentonite-water binder, using the apparent thermal coefficients. The majority of foundry simulation systems are not capable to modeling the phase transformation of water into vapor, vapor transport and its condensation in porous media (mould). In these cases the application of apparent coefficients is an effective way.

Influence of High Temperature Heat Sources on the Moisture and Temperature Distribution in a Real/Virtual Foundry Sand Mould

2016 ◽  
Vol 7 ◽  
pp. 69-83
Author(s):  
Paweł Popielarski ◽  
Zenon Ignaszak
Keyword(s):  
Cast Iron ◽  
Physical Properties ◽  
Rapid Heating ◽  
Temperature Fields ◽  
Coupled Modeling ◽  
Molding Sand ◽  
Mould Material ◽  
Sand Mould ◽  
Thermal Phenomena ◽  
Thermo Physical Properties

The problem described in the paper concerns the thermo-physical properties of the green mould material to which the cast iron is most often poured. The study includes the experiment of pouring the cast iron plate into green bentonite-sand mould. The temperature fields of casting and in different zones of the mould were recorded. The goal of the study was to determine the substitute thermo-physical properties of mould sand containing the over-moisture zone by means of simulation tests (inverse problem). An originality of the related research is an attempt to take into account the effects of the global thermal phenomena occurring in the quartz sand bonded by bentonite-water binder, by application of the substitute thermal coefficients without using the coupled modeling. In the simulation tests in order to achieve the effect of rapid heating of the mould (below temperatures 100 °C) by poured cast iron (T>1300 °C), the function of the latent heat source and the modified values of substitute thermal conductivity and substitute specific heat of the molding sand were used. In order to facilitate the solution, the mould was divided into zones, in which different starting humidity of molding sand was assumed.

A study on passive solar still with nanoparticles

2020 ◽  
pp. 26-38
Author(s):  
Vikas Kumar Thakur ◽  
Manoj Kumar Gaur
Keyword(s):  
Heat Transfer ◽  
Physical Properties ◽  
Saline Water ◽  
Solar Still ◽  
Passive Solar Still ◽  
Basin Water ◽  
Passive Solar ◽  
Transfer Properties ◽  
Thermo Physical Properties

In current paper shows the progressive effects of nanoparticles on the passive solar stills. Nanoparticles are used in SS because of their good thermo-physical properties, which affected the performance and efficiency of the SS, its increase the heat transfer properties of the basin water. Passive SS has very low productivity about 2-3 liters/m2 in a day. Many modifications have been done continuously by the researchers to increase the performance, productivity and efficiency of passive SSs. Various thermal storage materials are used in passive solar stills, such as wax (PCM), charcoal, fine stones and nanoparticles, to increase the productivity and also various methods is used like- by controlling the saline water depth, by controlling the glass angle and good quality of insulation for cover the still walls. The behavior of nanoparticles on the performance of passive SS has been studied and also study about the thermo-physical properties of the mixture of water and nanoparticles in present paper. Definitely, nanoparticles showed suitable characteristics and a favorable big applicability, based on improvement of thermal conductivity in comparison to base fluids free from additional metal or metal oxide nano scaled particles.

Determining Temperature Dependencies of Sand Mould Thermal Properties

2014 ◽  
Vol 790-791 ◽  
pp. 452-457 ◽  
Author(s):  
Paweł K. Krajewski ◽  
Grzegorz Piwowarski ◽  
Witold K. Krajewski
Keyword(s):  
Physical Properties ◽  
Numerical Models ◽  
Mass Density ◽  
Measuring Method ◽  
Casting Method ◽  
Mean Values ◽  
The Mean ◽  
Sand Mould ◽  
Thermo Physical Properties ◽  
Good Agreement

The presented work is aimed at determining thermal diffusivity, thermal conductivity and heat capacity coefficients of silica quartz bentonite foundry sand. The values of the above thermo-physical properties were determined for temperature range of about 30 - 450 °C using theCasting measuring method[1-.The results obtained during the examinations presented in the paper can be useful when formulating boundary conditions in numerical models of heat and mass transfer in the system: casting mould ambient. TheCasting methodallows preserving real conditions during the experiment, i.e. contact of the mass with liquid metal and solidifying casting, and the obtained results are in a good agreement with the mean values available in literature. From the obtained results it follows that examinations should be also focused onthermo-physical properties vs. mass densitydependency.

Effects of temperature-dependent thermo-physical properties on hydrodynamic swirl decay in microtubes

2018 ◽  
Vol 233 (3) ◽  
pp. 427-435 ◽  
Author(s):  
Sukumar Pati ◽  
Vishwanath Kumar
Keyword(s):  
Physical Properties ◽  
Swirling Flow ◽  
Slip Length ◽  
Temperature Fields ◽  
Temperature Dependent ◽  
Swirl Number ◽  
Constant Property ◽  
Swirl Velocity ◽  
Inlet Swirl ◽  
Thermo Physical Properties

In this paper, the influence of temperature-dependent thermo-physical properties is investigated on the decay of swirl in a laminar swirling flow of liquid through a heated microtube. The conservation equations for mass, momentum, and energy are numerically solved to obtain the velocity and temperature fields. The decay of swirl is quantified by the variation of the ratio of swirl number at a section to that at the inlet ( S/ S0) along the flow. The results reveal that constant property simulations result in faster swirl decay as compared to the variable-property simulations. Further, the implications of slip length, inlet swirl number, inlet swirl velocity profile, and Reynolds number on the swirl decay are presented. The results of the present analysis bear significant technological consequences in the design of micro-heat exchangers with intrinsic rotationalities.

scholarly journals A Recent Examination on the Performance of Heat Exchangers using Al2O3 Nanofluid with Its Thermo Physical Properties

2019 ◽  
Vol 9 (1S4) ◽  
pp. 653-656
Keyword(s):  
Thermal Conductivity ◽  
Physical Properties ◽  
Heat Exchangers ◽  
Preparation Method ◽  
Industrial Sites ◽  
Experimental Works ◽  
Alumina Nanofluid ◽  
Thermo Physical Properties ◽  
Al2o3 Nanofluid

Heat exchangers are the most significant equipment used in the industrial sites for exchanging the useful energy for many applications. It may be used either for cooling or heating but in the industrial scenario, it mostly used for cooling. In the current research development, the nanoparticles of different high thermal conductivity metals have been prepared and introduced in the low thermal performance base fluids like water, oil, ethylene glycol to enhance its quality of heat absorption in the heat exchangers. In that alumina nanoparticle played a significant role in many research applications and it has good thermal conductivity as a pure fluid. So, in this review work, the recent study of Al2O3 nanofluid with its preparation method, thermo-physical properties and its performance in varied heat exchangers have been discussed. This would enrich the knowledge and help the researchers who are interested in alumina nanofluid for their experimental works.

Simulation of vibration piercing of pipe blank at press

2020 ◽  
Vol 76 (11) ◽  
pp. 1128-1138
Author(s):  
S. R. Rakhmanov
Keyword(s):  
High Frequency ◽  
Deformation Zone ◽  
Pipe Blank ◽  
Equipment Operation ◽  
Metal Deformation ◽  
Technological Tool ◽  
High Frequency Vibrations ◽  
Pipe Blanks ◽  
Wave Phenomena

In some cases, the processes of piercing or expanding pipe blanks involve the use of high-frequency active vibrations. However, due to insufficient knowledge, these processes are not widely used in the practice of seamless pipes production. In particular, the problems of increasing the efficiency of the processes of piercing or expanding a pipe blank at a piercing press using high-frequency vibrations are being solved without proper research and, as a rule, by experiments. The elaboration of modern technological processes for the production of seamless pipes using high-frequency vibrations is directly related to the choice of rational modes of metal deformation and the prediction resistance indicators of technological tools and the reliability of equipment operation. The creation of a mathematical model of the process of vibrating piercing (expansion) of an axisymmetric pipe blank at a piercing press of a pipe press facility is an actual task. A calculation scheme for the process of piercing a pipe plank has been elaborated. A dependence was obtained characterizing the speed of front of plastic deformation propagation on the speed of penetration of a vibrated axisymmetric mandrel into the pipe workpiece being pierced. The dynamic characteristics of the occurrence of wave phenomena in the metal being pierced under the influence of a vibrated tool have been determined, which significantly complements the previously known ideas about the stress-strain state of the metal in the deformation zone. The deformation fields in the zones of the disturbed region of the deformation zone were established, taking into account the high-frequency vibrations of the technological tool. It has been established that the choice of rational parameters (amplitude-frequency characteristics) of the vibration piercing process of a pipe blank results in significant increase in the efficiency of the process, the durability of the technological tool and the quality of the pierced blanks.

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