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1

An experimental and numerical investigation of particles fluid dynamic flow and energy transfer in a heat exchanger. Part 1. An experimental and numerical granular material flowability study

Khumalo Samkelo M., Cieslakiewicz Waldemar F., Madyira Daniel M., Scholtz Dewald, Serfontein Jan

Technical Sciences / University of Warmia and Mazury in Olsztyn

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2025

|

Vol. 28

35--63

EN

Flowability is of great importance to a lot of processes especially granular material handling and heat transfer. In the industry achieving the highest heating efficiency of granular material heat exchanger is the most important factor. Heating/cooling area size is one of the critical factors in heat transfer processes and is highly dependent on flowability. The complexity of optimizing flowability can only be solved in two ways, either through experiment or computational modelling. However, the simulation technique is more time efficient and cost effective compared to the experimental analysis technique. Nonetheless, the CFD methodology requires prior validation of the model with the experiment. This study comprises of the experimental and numerical analysis of granular material flowability, and it aims at establishing a balanced flow of spherical silicon particles in a heat exchanger and developing a validated model that can be used for design optimisation. A Discrete Element Method (DEM) is employed in Simcenter STAR CCM+ to analyse the flow behaviour and is validated qualitatively and quantitatively from the experimental data. The results from both the simulation and the experiment exhibit a similar trend, indicating consistency between the two approaches. In both cases, the particle velocities are not uniform within the heat exchanger, as variations are observed across different regions, from 2 mm/s to 9 mm/s. Specifically, particles near the heat exchanger walls experience lower velocities due to higher frictional resistance, while those in the central flow stream, especially close to the outlet, move at relatively higher speeds. Quantitatively, the percentage difference between the simulation and experimental results is 9.53% for particle velocity and 5.61% for mass flow rate, which falls within an acceptable range for computational modelling of granular flow. This level of accuracy indicates that the simulation effectively captures the key flow dynamics within the heat exchanger, making it a reliable tool for further analysis. The study shows convincingly that the model was validated successfully, however investigated heat exchanger is highly inefficient but using the validated model can be optimized. The study comprises two parts. The first one presents the experimental and numerical particles flow analysis of the fluid (granular material), while the second one focuses on the experimental and numerical energy transfer (heating/cooling) analysis.

2

Ocena możliwości zastosowania wybranych mediów do granulacji materiałów sypkich

Derbiszewski Bogdan, Orczykowska Magdalena, Obraniak Andrzej

Przemysł Chemiczny

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2025

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T. 104, nr 8

774--778

PL

Przedstawiono ocenę możliwości zastosowania melasy buraczanej, szkła wodnego, alkoholu poliwinylowego i lignosulfonianu jako cieczy wiążących w procesie granulacji materiałów sypkich. Badano podstawowe właściwości fizyczno-chemiczne tych cieczy, takie jak gęstość właściwa, napięcie powierzchniowe i lepkość pozorna, która umożliwia ocenę ich płynności. Na podstawie uzyskanych wyników uszeregowano przebadane ciecze wg ich rosnących możliwości wiążących materiały sypkie poddawane procesowi granulacji.

EN

An assessment of the potential use of beet molasses, water glass, polyvinyl alcohol, and lignosulfonate as binding liqs. in the granulation of bulk materials was presented. Basic phys.-chem. properties of these liqs. were examined, such as d., surface tension, and apparent viscosity, which allows for the assessment of their fluidity. Based on the obtained results, the tested liqs. were ranked according to their increasing binding capabilities for bulk materials undergoing the granulation process.

3

Quality by design strategies in fluidized bed granulation: A focus on granules for tablet manufacturing

Przywara Mateusz, Leszczak Patryk

Advances in Science and Technology. Research Journal

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2025

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Vol. 19, no. 2

429--444

EN

The study aimed to apply the Quality by Design (QbD) methodology to optimize the fluidized-bed granulation process to produce high-quality pharmaceutical granules intended for tablet manufacturing. Research focused on defining the Quality Target Product Profile (QTPP) and identifying Critical Quality Attributes (CQAs), Critical Material Attributes (CMAs), and Critical Process Parameters (CPPs) crucial to ensuring product quality. The experimental design employed a three-level fractional factorial design to investigate the effects of key process parameters, including the mass flow rate of the binder, the temperature of the inlet air, and the drying time, on the granulation results. Measurements such as particle size distribution, moisture content, and flowability were used to assess the granules. The results indicated that parameters such as the inlet air temperature and drying time significantly impact the quality of the granules, confirming their status as CPPs. Further analysis of tablet mass and hardness revealed that these granule properties directly influenced tablet uniformity and mechanical strength.The application of the failure mode and effect analysis (FMEA) matrix helped to identify and prioritize these critical parameters based on their risk priority number (RPN). The study concluded that a systematic QbD approach, combined with a robust experimental design and risk management, is crucial for optimizing the fluidized-bed granulation process. This ensures consistent production of granules with the desired quality attributes and enhances the safety and efficacy of the final pharmaceutical product.

4

Effect of Particle Size, Lubricant, and Heat Temperature on the Flowability of Ni-Based Powders for Additive Manufacturing

Wang Huafang, Zhang Nan, Wang Miaohui, Yang Fang

Archives of Metallurgy and Materials

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2024

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Vol. 69, iss. 3

1005--1014

EN

Gas-atomized Ni-based powder tends to agglomerate, directly impacting the spreadability of printing process. In this paper, three technical methods are applied to restore the powder flowability, including regulating particle size distribution, lubricant modification, and heating treatment. As particle size increases, powder regains flowability. However, the average particle size of GH3536 powders with flowability is greater than 46 μm, which cannot meet the demand for 3D printing (15-53 μm). The flowability of GH3536 powder can be restored by adding zinc stearate lubricant. After lubricant modification, the printed samples display a 16% increase in elongation, along with a little improvement in tensile strength. This paper also investigates the flow properties change of raw powder heated at 100°C, 200°C, 300°C, and 400°C. When the temperature rises beyond 400°C, powder flowability fully returns, along with oxygen content increasing. Overall, the lubricant modification technique is appropriate in actual manufacturing, but the flow rate value of powders is typically high, exceeding 70 s/50 g. Increasing particle size and heat treatment can improve powder flowability and the flow rate of powder is less than 20 s/50 g.

5

Utilizing Taguchi Method and Regression Analysis for Optimizing Sand Mould Flowability

Abdulamer Dheya, Muhsan Ali A., Hamdi Sinan S.

Archives of Foundry Engineering

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2024

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Vol. 24, iss. 3

5--9

EN

Parameters of the moulding process in foundry are usually determined by trial-and-error method, and this way contributes to time taken and adds further cost for production sand. The present work represents an attempt to optimize sand moulding parameters in terms of compactability, compaction time, and air pressure, and to study effect of these factors on the green sand flowability using L4 design of experiments. Regression model, Taguchi method, and experimental verification were used to investigate flow property of sodium bentonite- bonded BP-quartz sand for sand moulding. Analysis of variance (ANOVA) was employed to measure significance and contributions of different moulding variables on flowability of green sand. The values obtained showed that the compaction time factor significantly affected flowability of green sand while compactability and air pressure have slight effects. The comparison results of Taguchi method, regression predictions and experiments exhibited good agreement.

6

The influence of long-distance pumping on the workability, mechanical strength, and frost resistance of SCC

Hao Ji, Meng Yuhao, Cui Yan, Mu Jinlei, Li Yue, Sui Chune

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 2

art. no. e91, 2024

EN

Concrete pumping technology is widely used in reservoirs, dams, harbours and other hydraulic structures. To investigate the effects of pumping on the flowability, mechanical strength and frost resistance of hydraulic concrete, long-distance pumping tests were carried out on self-compacting concrete (SCC). This paper investigated the influence of high-pressure pumping on the workability, mechanical strength and frost resistance of SCC by analysing the changes in various properties of SCC before and after long distance pumping. The flowability of the fresh concrete decreased after long-distance pumping. Compared to before pumping, the slump of the four groups of SCC decreased by an average of 3.93% and the slump-flow decreased by an average of 23.09%. The homogeneity and stability of the fresh SCC improved significantly after pumping. After pumping, the V-funnel time of SCC was reduced by an average of 82.32% and the segregation rate was reduced by an average of 125.76%. Additionally, there was a slight increase in mechanical strength indicated by an average increase of 5.87% in cubic compressive strength, 8.99% in axial compressive strength, 7.78% in tensile splitting strength, and 5.22% in modulus of elasticity. Notably, the frost resistance of the SCC showed significant improvement after pumping. Under non freeze-thaw conditions, the compressive strength of SCC after pumping increased by an average of 5.87%. After 200 freeze-thaw cycles, the compressive strength (after pumping) increased by an average of 12.46%. An air void analyser was then used to test the air-void parameters to analyse the effect of long-distance pumping action on the air voids parameters. The study further established the correlation between air-void structure characteristics and freeze-thaw resistance. Under freeze-thaw conditions, the compressive strength showed a linear correlation with air content and spacing factor. The process of pumping can enhance the air-void structure of SCC, leading to improved frost resistance. Therefore, in the design of concrete frost resistance, pumping can be considered as an influencing factor to improve the frost resistance of concrete.

7

Handling and transportation properties of rapeseed biomass as affected by particle size

Bojanowska Milena

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2023

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nr 74 (146)

5--15

EN

Rapeseed by-products of seeds de-oiling, particularly expellers and post-extracted meal, are currently considered an important biomass that can be used as an alternative energy source, either in raw form or after conversion to biochar. Rapeseed biomass represents a difficult-to-handle cargo, mainly due to its sensitivity to mechanical, climatic, and biological impacts, as well as its dusty nature. This study aims to determine the physical properties of rapeseed meals and their fractions. Morphological and chemical features of six particle sets are investigated in order to explain the variation in their physical properties having importance in handling and transportation processes. The true density of fractions increases when the particle size decreases due to the diminishing quantitative share of seed coats. No correlation is observed between true and bulk densities, as the particle shape, surface sculpture, and adhesion affect the mutual particle arrangements. Along with a decrease in the particle size from 0.4 mm, a rapid decrease in the flowability is observed. The tendency of the finest dust (d < 0.075 mm) to form agglomerated complexes causes its lower bulk density, higher porosity, and higher angles of repose in comparison to coarse dust (0.075–0.4 mm). It is concluded that a relatively low tendency to free flowing of natural RSM is mainly caused by its wide-ranging particle size distribution and their geometry differentiation, which facilitate mutual particle interlockings. The known cases of blockages of silos, bins, hoppers, and transfer chutes may be mainly caused by the powder fractions (< 0.2 mm), with a much lower flowability than other particles.

8

Numerical modelling of SS316L powder flowability for laser powder-bed fusion

Bouabbou A., Vaudreuil S.

Archives of Materials Science and Engineering

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2023

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Vol. 120, nr 1

22--29

EN

Purpose: This work aims to improve the powder-bed spreading process for laser powder bed fusion additive manufacturing by gaining a greater understanding of metal powder flowability through numerical modelling and in-situ experimentation. Design/methodology/approach: Using the Discrete Element Method (DEM) to study the flowability of the powder and its intrinsic properties. A high-fidelity particle-scale model was developed to capture the dynamics of metal particle interactions in a virtual Hall flow meter based on a modified Beverloo law. The results are validated experimentally using the Hall flow static powder characterisation technique. Findings: For SS316L powder alloy with the hall-value of 29s/50g and with an angle of repose (AOR) of 32°, the modelled powder that exhibited the same flow behaviour was found using 0.5 for both rolling and sliding coefficients resulting in simulated Hall value of 28.55s/50g with a simulated flow rate of 0.571 g/s, which is validated by AOR of the simulated powder [31.2°- 32.6°]. However, rolling friction had minimal effect on the mass flow rate but increased the angle of repose. Sliding friction significantly decreased the mass flow rate and increased AOR. Research limitations/implications: DEM is an ideal method to study flowability. However, there are certain constraints imposed on the computational power by a number of simulated particles and simulation time-step. Future research may involve investigating other dynamic flowability characterisation techniques. Practical implications: Enabling a better understanding of powder particle flow at a micro-scale by modelling powder flowability. This leads to simulating a more realistic powder bed and improving the powder spreading process, leading to better AM parts quality. Originality/value: This paper provides a unique approach for modelling the flowability of SS316L powder using a Beverloo law-based design of the Hall flow meter. This will improve the modelling of the spreading process needed for metal 3D printing.

9

Properties of binary blended cement mortars containing glass powder and steel slag powder

Dawood Eethar Thanon, Mhmood Marwa Saadi

Engineering Transactions

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2021

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Vol. 69, iss. 3

243--256

EN

The large quantity of waste or by-product materials (such as waste glass and steel slag) released to landfills is considered to be a real problem. The use of these materials as cement replacements makes it possible to solve this problem and reduce the quantity of carbon dioxide emitted from the cement manufacturing process. This paper presents the effect of waste glass powder (GP) and steel slag powder (SSP) on the properties of blended cement mortar. The flow, compressive strength, direct tensile strength and dry density of cement mortar containing GP and SSP as cement replacements with and without superplasticizer (SP) are studied and compared with the control mix. The results show that the glass and steel slag powders, once they are simultaneously added as a ternary blended cement mortar, reduce the water binder ratio required to achieve flowability. Additionally, the compressive strength results of such blended mortar showed that the increased GP content exhibits better performance than that of slag powder for the same level of waste materials replacements.

10

Investigation of flowability of the green sand mould by remote control of portable flowability sensor

Abdulamer D.

Archives of Materials Science and Engineering

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2021

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Vol. 112, nr 2

70--76

EN

Purpose: The useful data and information during the sand compaction process steps should be collected. Direct measurement methods of the sand mould properties during the actual moulding process are not adopted yet. Design/methodology/approach: In this work, a remote control system [1] have been integrated into a new flowability sensor [2]. Findings: To overcome the complexity of the tools and equipment that existed in laboratory, and in foundry. Research limitations/implications: In order to investigate, and control behavior of the moulding process of bentonite-bonded green sand process, the sensors have been equipped with the Bluetooth technology for a wireless transmission of the measured data to computers. Originality/value: This technique contributes to improve of the compaction process based on the non-destructive tests, enhances prediction of the optimum parameter conditions, and reduced the energy, and the compaction time consumed for the green sand moulding process.

11

Flowability of Moist Coal Combution Fly Ash

Lanzerstorfer Christof

Inżynieria Mineralna

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2019

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R. 21, nr 1

95--98

EN

In the combustion of coal the mineral contents remain as ash. The fine size fraction of the ash leaves the combustion zone with the off-gas from which it is separated as fly ash. Depending on the physical and chemical properties these fly ashes can be utilized. An essential parameter for the design and operation of transport equipment and storage facilities for fine grained materials is their flowability. The moisture content of the material has considerable influence on the flowability because of the increasing influence of the liquid bridges between the particles and the resulting capillary forces. In this study the influence of the moisture content on the flow characteristics of a coal combustion fly ash was investigated. The fly ash sample was collected from the dust discharge of the electrostatic precipitator of a power plant using Polish hard coal as fuel. The mass median diameter of the fly ash was approximately 20 µm. Microscopic images show that most of the particles are spheres. The flow properties of the fly ash were measured using a ring shear tester. The moisture content of the sample was adapted by addition of water. The dry fly ash was characterized by very good flow properties, the flowability ffc was in the category ‘easy flowing’. Significant decrease in flowability was found at increased moisture contents. Additionally, the bulk density of the fly ash was influenced by the moisture content. Thus, the flow-relevant parameters which have to be considered in design of transport and storage facilities of fine granular material worsened with increasing moisture content.

PL

Przy spalaniu węgla zawarte w nim minerały pozostają w postaci popiołu. Drobna frakcja popiołu opuszcza strefę spalania z gazem odlotowym, z którego jest oddzielana jako popiół lotny. W zależności od właściwości fizycznych i chemicznych można wykorzystać popioły lotne. Istotnym parametrem dla projektowania i eksploatacji urządzeń transportowych i magazynów materiałów drobnoziarnistych jest ich zdolność płynięcia. Zawartość wilgoci w materiale ma znaczący wpływ na zdolność płynięcia ze względu na rosnący wpływ mostków cieczowych między cząstkami i wynikającymi z nich siłami kapilarnymi. W pracy zbadano wpływ zawartości wilgoci na charakterystykę przepływu popiołu lotnego ze spalania węgla. Próbka popiołu lotnego została pobrana z odbiornika pyłu z elektrofiltra elektrowni z wykorzystaniem polskiego węgla kamiennego jako paliwa. Mediana średnicy ziarna popiołu lotnego wynosiła około 20 μm. Obrazy mikroskopowe pokazują, że większość cząstek to kule. Właściwości przepływu popiołu lotnego mierzono za pomocą testera ścinania pierścieniowego. Zawartość wilgoci w próbce zmieniano przez dodatek wody. Suchy popiół lotny charakteryzował się bardzo dobrymi właściwościami płynięcia, płynność ffc była w kategorii „łatwo płynący”. Znaczny spadek płynności stwierdzono przy zwiększonej zawartości wilgoci. Dodatkowo zawartość wilgoci ma wpływ na gęstość nasypową popiołu lotnego. Zatem istotne dla przepływu parametry, które należy wziąć pod uwagę przy projektowaniu urządzeń do transportu i przechowywania drobnego materiału ziarnistego, pogarszają się wraz ze wzrostem zawartości wilgoci.

12

Evaluation of Buckwheat Product Properties for Discrete Element Model (DEM) Simulation

Jezerska Lucie, Zidek Martin, Zegzulka Jiri, Palkovska Barbora

Inżynieria Mineralna

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2019

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R. 21, nr 1/2

155--158

EN

The paper deals with various types of buckwheat products (Fagopyrum esculentum Moench), which have been determined with mechanical and physical properties in order to provide useful data for engineers to design structures of used equipment, harvesting and other processing technologies. Buckwheat is currently a well-sought-after food in the field of healthy nutrition, especially because of its high fiber content, iron and potassium. Among the tested samples were, for example, buckwheat hazelnuts, chips, flakes and others. In the above mentioned, the parameters of the linear dimensions, the Carrs index, the Hausner ratio and the flow rate were measured and compared. The influence of geometric parameters of buckwheat products was determined on mechanical and physical properties. The first results showed that the set parameters were statistically different for each type of buckwheat. On the basis of measured data, a simulation of the flow of a specific buckwheat sample was performed. The discrete element (DEM) method used for this purpose appears to be an appropriate tool for transporting these agricultural products.

PL

Artykuł dotyczy różnych rodzajów produktów z gryki (Fagopyrum esculentum Moench), które zostały określone za pomocą właściwości mechanicznych i fizycznych w celu dostarczenia inżynierom przydatnych danych do projektowania struktur używanych urządzeń, zbiorów i innych technologii przetwarzania. Gryka jest obecnie popularnym pożywieniem w dziedzinie zdrowego żywienia, szczególnie ze względu na wysoką zawartość błonnika, żelaza i potasu. Wśród badanych próbek były orzechy laskowe, gryka, chipsy, płatki i inne. Zmierzono i porównano parametry wymiarów liniowych, wskaźnik Carrsa, współczynnik Hausnera i natężenie przepływu. Określono wpływ parametrów geometrycznych produktów z gryki na właściwości mechaniczne i fizyczne. Wyniki wykazały, że zmierzone i założone parametry były statystycznie różne dla każdego rodzaju gryki. Na podstawie zmierzonych danych przeprowadzono symulację przepływu określonej próbki gryki. Zastosowana w tym celu metoda elementów dyskretnych (DEM) wydaje się odpowiednim narzędziem do opisu transportu tych produktów rolnych.

13

Lightweight self-compacting concrete with sintered fly-ash aggregate

Małaszkiewicz D., Jastrzębski D.

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

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2018

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Vol. 27, No. 3

328--337

EN

The article presents the results of research assessing the possibility of making LWSCC from the locally produced sintered fly ash aggregate CERTYD. Two methods of preliminary LWA preparation were applied: pre-soaking with water and coating with a film of cement paste. The following properties of fresh LWSCC were evaluated: slump-flow, time T500 and passing ability using L-Box. Partial replacement of natural sand by fine LW sand (0/0.5 mm) improved filling and passing abilities of fresh concrete, reduced slightly the bulk density, but it resulted in compressive strength loss by 12-18%. In terms of both fresh and hardened concrete properties it is more favorable to use only fine LW sand as natural sand replacement. Considering fresh concrete properties paste impregnation of LW aggregate is more efficient than saturation with water.

14

Ocena wybranych napojów roślinnych w proszku – charakterystyka właściwości fizykochemicznych

Ruszkowska M., Wiśniewska A.

Zeszyty Naukowe Akademii Morskiej w Gdyni

|

2017

|

nr 99

103--113

PL

Celem pracy była ocena właściwości fizykochemicznych wybranych napojów roślinnych w proszku. Materiał badawczy stanowił proszek napoju kokosowego (I), sojowego (II), ryżowego (III), owsianego (IV). Metodyka badań obejmowała oznaczenie zawartości wody, aktywności wody, gęstości luźnej i utrzęsionej, współczynnika Hausnera, indeksu Carra, kąta nasypu oraz zwilżalności. Na podstawie przeprowadzonych badań stwierdzono, że właściwości fizykochemiczne badanych napojów roślinnych w proszku determinował skład surowcowy oraz proces technologiczny zastosowany przez poszczególnych producentów.

EN

The aim of the study was to evaluate the physicochemical properties of selected drinks vegetable powder. The research material was coconut drink powder (I), soybean (II), rice (III), oat (IV). The research methodology included the determination of water content, water activity, loose and tapped density, Hausner ratio and, Carr index, angle of repose and wettability. Based on the survey, it was found that the physicochemical properties of the tested beverage plant powder were determined the composition of raw materials and technological process used by various manufacturers.

15

The influence of coarse aggregate shape on the properties of high-performance, self-compacting concrete

Ostrowski K.

Technical Transactions

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2017

|

Vol. 5(114)

25--33

EN

High-performance, self-compacting concrete (HPSCC) represents a very significant step in the development of concrete technology. The most important features of SCC are specific rheological properties which include flowability, segregation resistance and passing ability. Therefore, a crucial requirement is to maintain an appropriate balance between the slump flow and plastic viscosity of concrete mixtures. In general, the rheological properties are modified by effective superplasticisers and a proper ratio of water to binder. The aim of this study is to focus on the important aspect of the impact of shape of the coarse aggregate on fresh concrete mixture properties and the strength of high-performance, self-compacting concrete (HPSCC).

PL

Samozagęszczalny beton wysokowartościowy stanowi bardzo istotny krok w rozwoju technologii betonu. Najistotniejszą cechą betonu samozagęszczalnego są specyficzne właściwości reologiczne mieszanki, do których zaliczamy płynność, stabilność i zdolność do przepływu przez zbrojenie. Bardzo ważne jest więc zachowanie odpowiedniego balansu pomiędzy granicą płynięcia a lepkością plastyczną mieszanki. Na ogół właściwości reologiczne są modyfikowane poprzez stosowanie efektywnych superplastyfikatorów oraz odpowiedni stosunek wodno-spoiwowy. Celem niniejszej pracy jest zwrócenie uwagi na istotny aspekt wpływu foremności ziaren kruszywa na właściwości reologiczne świeżej mieszanki betonowej oraz wytrzymałość samozagęszczalnego betonu wysokowartościowego.

16

Wpływ obróbki powierzchniowej na lutowność stali 410

Babul T., Kondej A., Kowalski S., Baranowski M., Lankiewicz K.

Przegląd Spawalnictwa

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2016

|

R. 88, nr 3

14--18

PL

W pracy określono wpływ obróbki powierzchniowej stali 410 na lutowność przy zastosowaniu lutu na bazie miedzi. Do przygotowania powierzchni wybrano kilka metod: odtłuszczanie, trawienie, szlifowanie, obróbkę strumieniowo-ścierną, niklowanie oraz NicroBlasting®. Lutowność oceniano na podstawie wyników badań rozpływności lutowia na podłożu stalowym. Dodatkowo zbadano wpływ obróbki powierzchniowej na lutowność odlewów staliwnych 410 miedzianym. Przeprowadzono badania na mikroskopie skaningowych oraz wykonano analizę EDS rozkładu pierwiastków w złączu.

EN

The influence of the surface treatment of steel 410 on brazeability using filler metal based on copper has been determined in this paper. For surface preparation there have been chosen several methods: degreasing, etching, sanding, abrasive blasting, nickel electroplating and NicroBlasting®. Brazeability was evaluated on the basis of the flowability test results on steel surface. In addition, the influence of the surface treatment on the brazeability of steel 410 castings brazed using copper filler metal was investigated. Studies on the scanning electron microscope and EDS analysis of the distribution of elements in the joint were carried out.

17

Investigation of Some Moulding Properties of a Nigerian Clay-Bonded Sand

Oke A. O., Omidiji B. V.

Archives of Foundry Engineering

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2016

|

Vol. 16, iss. 3

71--76

EN

Moulding properties of Isasa River Sand bonded with Ipetumodu clay (Ife-North Local Government Area, Osun State, Nigeria) were investigated. American Foundry men Society (AFS) standard cylindrical specimens 50mm diameter and 50mm in height were prepared from various sand and clay ratios (between 18% and 32%) with 15% water content. The stress-strain curves were generated from a universal strength testing machine. A flow factor was calculated from the inclination of the falling slope beyond the maximum compressive strength. The result shows that the flowability of the samples increases from 18% to 26% clay content, its maximum value was attained at 26% and then it decreases from 30% to 32% clay content. The green compressive strength, dry compressive strength and air permeability values obtained from the mould samples were in accordance with standard values used in foundry practice. The x-ray diffraction test shows that the sand contains silicon oxide (SiO2), Aluminium oxide (Al2O3), and Aluminium silicate (Al6Si2O13). The mould samples were heated to a temperature of 1200 oC to determine the sintering temperature; fussion did not take place at this temperature. The results showed that the sand and clay mixture can be used to cast ferrous and non-ferrous alloys.

18

Badanie wpływu wilgoci na sypkość sody w produkcji detergentów

Korpyś M., Raczek J., Moń S., Wójcik J.

Przemysł Chemiczny

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2015

|

T. 94, nr 3

287-290

PL

Przedstawiono wyniki badań wpływu wilgoci na sypkość surowca w produkcji detergentów. Pomiarów dokonano, wykorzystując urządzenie opracowane w Katedrze Inżynierii Chemicznej i Projektowania Procesowego Politechniki Śląskiej w Gliwicach. W wyniku przeprowadzonych badań stwierdzono silny wpływ wilgoci na obniżenie sypkości materiału, co może być przyczyną zawieszania się sody w zbiornikach dozujących.

EN

Four samples of com. soda ash were studied for bulk d., grain size distribution and flowability at varying air humidity and moisture contents. The flowability index decreased with the increasing moisture content in the soda ash grains.

19

Optimisation Of Process Parameters In High Energy Mixing As A Method Of Cohesive Powder Flowability Improvement

Leś K., Kowalski K., Opaliński I.

Chemical and Process Engineering

|

2015

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Vol. 36, nr 4

449--460

EN

Flowability of fine, highly cohesive calcium carbonate powder was improved using high energy mixing (dry coating) method consisting in coating of CaCO3 particles with a small amount of Aerosil nanoparticles in a planetary ball mill. As measures of flowability theangle of repose and compressibility index were used. As process variables the mixing speed, mixing time, and the amount of Aerosil and amount of isopropanol were chosen. To obtain optimal values of the process variables, a Response Surface Methodology (RSM) based on Central Composite Rotatable Design (CCRD) was applied. To match the RSM requirements it was necessary to perform a total of 31 experimental tests needed to complete mathematical model equations. The equations that are second-order response functions representing the angle of repose and compressibility index wereexpressed as functions of all the process variables. Predicted values of the responses were found to be in a g ood agreement with experimental values. The models were presented as 3-D response surface plots from which the optimal values of the process variables could be correctly assigned. The proposed, mechanochemical method of powder treatment coupled with response surface methodology is a new, effective approach to flowability of cohesive powder improvement and powder processing optimisation.

20

Paliwo zawiesinowe z polskich węgli energetycznych do procesu zgazowania

Robak J., Ignasiak K., Muzyka R.

Przegląd Górniczy

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2013

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T. 69, nr 7

61--66

PL

W artykule przedstawiono rezultaty badań nad otrzymywaniem węglowych paliw zawiesinowych na bazie potencjalnie dostępnych do procesu zgazowania, polskich węgli energetycznych – węgla ZG „Janina” i kopalni „Wieczorek”. Właściwości badanych węgli porównano z wymaganiami stawianymi surowcom węglowym do wytwarzania paliwa w formie zawiesiny wodnej – dwa badane węgle są przykładem węgli energetycznych o niskim stopniu metamorfizmu, nie spełniających tych wymagań. Zawiesiny wytwarzano bez i z zastosowaniem dyspergatora w postaci soli sodowych kwasów naftalenosulfonowych (dyspergator NNOS E). Zwiększano koncentrację fazy stałej w zawiesinie, jednocześnie badając zdolność płynięcia (warunek konieczny do realizacji kolejnych badań), lepkość i stabilność wytworzonych produktów. Stwierdzono, że korzystniejszymi właściwościami sprzyjającymi wytwarzaniu stabilnych suspensji węglowo-wodnych charakteryzuje się węgiel „Wieczorek”. Jego wykorzystanie pozwala na uzyskanie zawiesiny o koncentracji 58 % i dobrych pozostałych walorach technologicznych: zdolności płynięcia, lepkości i stabilności w czasie.

EN

This paper presents the results of a study on the preparation of coal-based fuels from Polish coals, potentially available for the gasification process: coals from ZG ”Janina” and KWK ”Wieczorek”. The properties of the tested coals were compared to the raw material requirements of coal-slurry fuel production. Both coals are examples of low metamorphic coals and do not meet these requirements.The slurries were prepared with and without a dispersant, containing sodium salts from naphthalenesulfonic acid (dispersant NNOS E). Concentration of solid phase in the slurry was gradually being increased and, simultaneously, flowability (necessary for further studies), viscosity and stability of the prepared products was measured. More positive properties, favoring the production of stable water-coal suspensions, were present in ”Wieczorek” coal. Its use allows to obtain a slurry of 58 % concentration as well as other good technological properties, such as flowability, viscosity and stability over time.