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This article presents the device and the principle of operation of forage grain crushers that use the centrifugal force of inertia to supply the working bodies—which occurs as a result of rotation of the rotor with a vertical axis. The results of some tests of machines working on this principle have been characterized. Attention is drawn to the disadvantages of most research works, namely the lack of premises for creating shredders of this class with a wide range of performance. The aim of this work is to establish the relationship between the design and technological parameters for the operation of a centrifugal-rotary shredder using the theory of similarity and a dimensional analysis. Moreover, the experimental data show an empirical relationship when calculating the efficiency for the shredder model considered above. By applying the similarity criteria, dimensionless complexes were obtained, which allow to determine the significance of the parameters selected at the initial stage for the efficiency of the shredder. The novelty of this research is the application of the theory of similarity and the use of dimensional analysis, which allowed for scaling the results of the experimental data and obtaining a centrifugal-rotary shredder with higher efficiency, while maintaining the quality of the obtained product. This technique indicates the energy costs of the grinding process, which can be used to select the ratio of parameters in the shredder that would ensure that a minimum amount of energy is consumed.
Wacław Romaniuk; Petr Savinykh; Kinga Borek; Kamil Roman; Alexey Isupov; Aleksandr Moshonkin; Grzegorz Wałowski; Michał Roman. The Application of Similarity Theory and Dimensional Analysis to the Study of Centrifugal-Rotary Chopper of Forage Grain. Energies 2021, 14, 4501 .
AMA StyleWacław Romaniuk, Petr Savinykh, Kinga Borek, Kamil Roman, Alexey Isupov, Aleksandr Moshonkin, Grzegorz Wałowski, Michał Roman. The Application of Similarity Theory and Dimensional Analysis to the Study of Centrifugal-Rotary Chopper of Forage Grain. Energies. 2021; 14 (15):4501.
Chicago/Turabian StyleWacław Romaniuk; Petr Savinykh; Kinga Borek; Kamil Roman; Alexey Isupov; Aleksandr Moshonkin; Grzegorz Wałowski; Michał Roman. 2021. "The Application of Similarity Theory and Dimensional Analysis to the Study of Centrifugal-Rotary Chopper of Forage Grain." Energies 14, no. 15: 4501.
Underground coal gasification (UCG) technology converts deep coal resources into synthesis gas for use in the production of electricity, fuels and chemicals. This study provides an overview of the systematic methods of the in situ coal gasification process. Furthermore, the model of the porous structure of coal has been presented and the gas movement taking place in the carbon matrix—which is part of the bed—has been described. The experimental tests were carried out with the use of air forced through the nozzle in the form of a gas stream spreading in many directions in a porous bed under bubbling conditions. The gas flow resistance coefficient was determined as a function of the Reynolds number in relation to the diameter of the gas flow nozzle. The proprietary calculation model was compared to the models of many researchers, indicating a characteristic trend of a decrease in the gas flow resistance coefficient with an increase in Reynolds number. The novelty of the study is the determination of the permeability characteristics of char (carbonizate) in situ in relation to melted waste rock in situ, taking into account the tortuosity and gas permeability factors for an irregularly shaped solid.
Grzegorz Wałowski. Gas Permeability Model for Porous Materials from Underground Coal Gasification Technology. Energies 2021, 14, 4462 .
AMA StyleGrzegorz Wałowski. Gas Permeability Model for Porous Materials from Underground Coal Gasification Technology. Energies. 2021; 14 (15):4462.
Chicago/Turabian StyleGrzegorz Wałowski. 2021. "Gas Permeability Model for Porous Materials from Underground Coal Gasification Technology." Energies 14, no. 15: 4462.
With regard to the problem of gas flow through isotropic porous deposits, the issues were considered in the category of description of gas movement mechanisms for structural models of the skeleton. As part of experimental tests of gas permeability through porous material in the form of polyamide, the numerical simulation method was used, using the k–ε turbulence model. The analysis of hydrodynamic phenomena occurring in the porous material made it possible to confront experimental research with numerical calculations. The analysis shows that, for a porous polyamide bed, there is a certain limit range of gas velocity (10−4–1) ms−1 at which flow resistance is the lowest. On the other hand, the highest value of the flow resistance is gradually achieved in the range of gas velocity (1–10) ms−1. This is due to the different structure of the isotropic polyamide material. The validation of the numerical model with experimental data indicates the validity of the adopted research methodology. It was found that the permeability characteristics of the tested porous material practically did not depend on the direction of gas flow. For porous polyamide, the permeability characteristic is non-linear, which, from the point of view of the measurements carried out, indicates the advantage of turbulent gas flow over its laminar movement. The novelty of the article is a proprietary method of measuring gas permeability for a cube-shaped sample made of a material constituting a sinter of spherical particles of equal dimensions. The method enables the determination of gas flow (in each flow direction) in microchannels forming an orthogonal network, characteristic of isotropic materials.
Grzegorz Wałowski. Experimental and Numerical Studies of Gas Permeability through Orthogonal Networks for Isotropic Porous Material. Materials 2021, 14, 3832 .
AMA StyleGrzegorz Wałowski. Experimental and Numerical Studies of Gas Permeability through Orthogonal Networks for Isotropic Porous Material. Materials. 2021; 14 (14):3832.
Chicago/Turabian StyleGrzegorz Wałowski. 2021. "Experimental and Numerical Studies of Gas Permeability through Orthogonal Networks for Isotropic Porous Material." Materials 14, no. 14: 3832.
The properties, types, and physical and chemical aspects of pig slurry used in the fermentation process were presented. Characterization of the pig slurry microflora for a controlled biogas production process was performed. A pilot biogas treatment installation was presented on the example of a farm with 1100 Dan Bred fatteners kept in a grate system. The research was carried out to measure the biogas flow rate resulting from the reference pressure in the fermentor. An independent assessment of the amount of biogas and the pressure drop in the skeletal deposit was carried out. The basis for assessing the hydrodynamics of gas flow through the adhesive bed is the flow characteristic, which results from the pressure that forces this flow. In each case, the determination of this characteristic consists in determining the influence of the biogas stream on the value of this overpressure, equivalent to the pressure drop (it is tantamount to determining the total biogas flow resistance through the adhesive bed). The results of the measurements indicate the practical application of pig slurry-a substrate in a polydisperse system for the production of agricultural biogas in the context of renewable energies. The article indicates that the ferment was periodically mixed during the day, together with the fermentation of the ferment with fresh substrate. The tests were conducted for 49 days, thus demonstrating that it is more advantageous to mix the ferment hydrodynamically, obtaining a CH4 level of about 80%.
Kamila Klimek; Magdalena Kapłan; Serhiy Syrotyuk; Ryszard Konieczny; Dorota Anders; Barbara Dybek; Agnieszka Karwacka; Grzegorz Wałowski. Production of Agricultural Biogas with the Use of a Hydrodynamic Mixing System of a Polydisperse Substrate in a Reactor with an Adhesive Bed. Energies 2021, 14, 3538 .
AMA StyleKamila Klimek, Magdalena Kapłan, Serhiy Syrotyuk, Ryszard Konieczny, Dorota Anders, Barbara Dybek, Agnieszka Karwacka, Grzegorz Wałowski. Production of Agricultural Biogas with the Use of a Hydrodynamic Mixing System of a Polydisperse Substrate in a Reactor with an Adhesive Bed. Energies. 2021; 14 (12):3538.
Chicago/Turabian StyleKamila Klimek; Magdalena Kapłan; Serhiy Syrotyuk; Ryszard Konieczny; Dorota Anders; Barbara Dybek; Agnieszka Karwacka; Grzegorz Wałowski. 2021. "Production of Agricultural Biogas with the Use of a Hydrodynamic Mixing System of a Polydisperse Substrate in a Reactor with an Adhesive Bed." Energies 14, no. 12: 3538.
The hydrodynamic conditions resulting from the permeability of porous materials are based not only on the assessment of the gas flow through these materials, but also the losses related to the pressure energy in this flow. Flow resistance is a direct measure of this loss. The aim of this experimental research was to evaluate the flow resistance of the porous material in relation to the gas flow. The research was carried out on a material with a slit-porous structure. The tests were carried out on a system for measuring gas permeability under the conditions of gas bubbling through the char. The issue of the total pressure drop process in the porous bed was considered in the Reynolds number category. The coefficient of flow resistance for the char was determined and the value of this coefficient was compared with the gas stream, and an experimental evaluation of the total pressure drop on the porous bed was made. The novelty of this article is the determination of the tortuosity and the gas permeability coefficient for a solid of any shape—a rigid skeleton.
Grzegorz Wałowski. Model of Flow Resistance Coefficient for a Fragment of a Porous Material Deposit with Skeletal Structure. Energies 2021, 14, 3355 .
AMA StyleGrzegorz Wałowski. Model of Flow Resistance Coefficient for a Fragment of a Porous Material Deposit with Skeletal Structure. Energies. 2021; 14 (11):3355.
Chicago/Turabian StyleGrzegorz Wałowski. 2021. "Model of Flow Resistance Coefficient for a Fragment of a Porous Material Deposit with Skeletal Structure." Energies 14, no. 11: 3355.
The article describes the technical and process aspects of the technology resulting from the thermal processing of coal in an unconventional way. Selected methods of assessing gas permeability through a porous bed, which is characterized by hydrodynamic gas flow, are indicated. The presented measurement results indicate a clear impact of the type of material on gas permeability and the impact of flow directivity on the value of the gas stream. A new method of hydrodynamic assessment of the permeability coefficient was pointed out, which was correlated with selected criteria characteristic for porous materials derived from coal gasification technology. Based on the process assessment of the research results, it was found that it is useful to use such hydrodynamic features as horizontal, vertical and effective gas permeability coefficient. These values can be used to identify technological quality indicators for raw gas, which is a product of Underground Coal Gasification. The reason for writing this article is the current nature of this topic, which results from the observed reason for the so-called clean coal technologies and the development of modern clean energy technologies that give rise to alternative energy sources, especially renewable energy sources.
Grzegorz WaŁowski. The method to assess the gas flow of a porous bed product derived from underground coal gasification technology. Energy 2020, 199, 117456 .
AMA StyleGrzegorz WaŁowski. The method to assess the gas flow of a porous bed product derived from underground coal gasification technology. Energy. 2020; 199 ():117456.
Chicago/Turabian StyleGrzegorz WaŁowski. 2020. "The method to assess the gas flow of a porous bed product derived from underground coal gasification technology." Energy 199, no. : 117456.
The aim of this study was to perform a comparative analysis of the unit gas emission value in the exhaust of a dual fuel diesel engine. The results of the effects of a diesel engine’s applications in biogas plants and the method for calculating mass gas emissions per unit of produced electricity are shown. The test was performed using a two-cylinder, naturally aspirated, liquid-cooled diesel engine. The diesel engine powered a generator connected to the grid. The engine was fed with liquid fuels—waste cooking oil methyl ester (UCOME) and diesel fuel (DF)—and with a gas fuel, biogas (BG). The engine ran at a constant rotational speed (2000 rpm ± 30 rpm) with variable load. The gas analyzer measured the amount of CO, NO, NO2, and PM (particulate matter) in exhaust gas. This gas content share was then converted to mass per engine generated energy unit. This experiment showed the effect of BG introduced to the intake manifold on fuel combustion, as well as an increase in CO and NO2 emission and decrease in NO and PM. In terms of dependence of exhaust emissions on the type of liquid fuel used, the use of UCOME as opposed to diesel fuel resulted in PM reduction and increase of NO emissions.
Wojciech Golimowski; Paweł Krzaczek; Damian Marcinkowski; Weronika Gracz; Grzegorz Wałowski. Impact of Biogas and Waste Fats Methyl Esters on NO, NO2, CO, and PM Emission by Dual Fuel Diesel Engine. Sustainability 2019, 11, 1799 .
AMA StyleWojciech Golimowski, Paweł Krzaczek, Damian Marcinkowski, Weronika Gracz, Grzegorz Wałowski. Impact of Biogas and Waste Fats Methyl Esters on NO, NO2, CO, and PM Emission by Dual Fuel Diesel Engine. Sustainability. 2019; 11 (6):1799.
Chicago/Turabian StyleWojciech Golimowski; Paweł Krzaczek; Damian Marcinkowski; Weronika Gracz; Grzegorz Wałowski. 2019. "Impact of Biogas and Waste Fats Methyl Esters on NO, NO2, CO, and PM Emission by Dual Fuel Diesel Engine." Sustainability 11, no. 6: 1799.
The results of experimental studies in the field of gas permeability of porous materials referring to gas flow have been shown. Coal chars with anisotropic porous-slotted structure have been tested. The studies have been carried out on a special test bench that allows for the measurement of gas permeability in terms of three flow orientations related to symmetrical specimens in the cubic form. The results of the measurements indicate that there is a considerable effect of the flow directivity on the permeability of carbonizers, which results from their integral anisotropic structure. A permeability coefficient for such materials has been defined and the experimental assessment of the value of this coefficient against gas flow and the total pressure drop on a porous medium has been made. The usefulness of computation methods characterising the hydrodynamics of gas flow through porous materials has been made, and the possibility of a numerical mapping of the flow geometry of solid materials with tortuous structure has been indicated.
Grzegorz WaŁowski; Gabriel Filipczak. Assessment of gas permeability through porous skeletal media with anisotropic internal structure. MATEC Web of Conferences 2018, 240, 01035 .
AMA StyleGrzegorz WaŁowski, Gabriel Filipczak. Assessment of gas permeability through porous skeletal media with anisotropic internal structure. MATEC Web of Conferences. 2018; 240 ():01035.
Chicago/Turabian StyleGrzegorz WaŁowski; Gabriel Filipczak. 2018. "Assessment of gas permeability through porous skeletal media with anisotropic internal structure." MATEC Web of Conferences 240, no. : 01035.
The hydrodynamic results obtained from the permeability of porous materials not only affect the assessment of the stream of the gas flow through those materials but they also refer to the loss of pressure energy in that flow. The direct measure of that loss is flow resistances.The results of experimental research upon the assessment of the flow resistances of porous materials with respect to gas flow. The research conducted applied to natural materials with an anisotropic gap-porous structure. The tests were carried out on a gas permeability measuring system, adapted to different shapes of porous material samples. The process issue of the total pressure drop on a porous deposit was considered in the Reynolds number category. The coefficient of flow resistance for anisotropic materials was defined and the value of this coefficient was compared to the gas stream and the total pressure drop on the porous bed was experimentally evaluated.
Grzegorz WaŁowski. Model of Flow Resistance Coefficient for a Fragment of a Porous Material Deposit with Anisotropic Skeletal Structure. 2018, 1 .
AMA StyleGrzegorz WaŁowski. Model of Flow Resistance Coefficient for a Fragment of a Porous Material Deposit with Anisotropic Skeletal Structure. . 2018; ():1.
Chicago/Turabian StyleGrzegorz WaŁowski. 2018. "Model of Flow Resistance Coefficient for a Fragment of a Porous Material Deposit with Anisotropic Skeletal Structure." , no. : 1.
The assessment of process phenomena resulting from the hydrodynamics of gas flow through various kinds of coal chars may refer to a vast number of technological aspects pertaining to qualitative features of those materials. Those issues are subject to the assessment of the post-reaction gas movement in the conditions of the thermal processing of coal substances. In the case, an additional aspect of this assessment is also phenomena referring to the determination of the permeability of coal chars in the context of their application in other technological processes, e.g. coke in the metallurgical cycle. In the context of research upon the hydrodynamics of gas flow through porous materials an attempt was made to correlate the results of that research with the process issues resulting from the technological reasons for applying various kinds of coal chars. This correlation was referred to the assessment of the technological quality of coke referring to its features for the blast furnace technology. The basis for the assessment was the obtained results referring to the measurement of structural features of the analysed coal chars and the hydrodynamics resulting from their gas permeability.
Grzegorz Wałowski. Assessment of coke quality related to of effective permeability coefficient and anisotropy coefficient. Fuel 2018, 236, 82 -91.
AMA StyleGrzegorz Wałowski. Assessment of coke quality related to of effective permeability coefficient and anisotropy coefficient. Fuel. 2018; 236 ():82-91.
Chicago/Turabian StyleGrzegorz Wałowski. 2018. "Assessment of coke quality related to of effective permeability coefficient and anisotropy coefficient." Fuel 236, no. : 82-91.
This study discusses results of experiments on hydrodynamic assessment of gas flow through backbone (skeletal) porous materials with an anisotropic structure. The research was conducted upon materials of diversified petrographic characteristics, both natural origin (rocky, pumice) and process materials (char and coke). The study was conducted for a variety of hydrodynamic conditions, using air, as well as for nitrogen and carbon dioxide. The basis for assessing hydrodynamics of gas flow through porous material was a gas stream that results from the pressure forcing such flow. The results of measurements indicate a clear impact of the type of material on the gas permeability, and additionally – as a result of their anisotropic internal structure – to a significant effect of the flow direction on the value of gas stream.
Grzegorz WaŁowski; Gabriel Filipczak. Klinkenberg effect in hydrodynamics of gas flow through anisotropic porous materials. E3S Web of Conferences 2017, 19, 3008 .
AMA StyleGrzegorz WaŁowski, Gabriel Filipczak. Klinkenberg effect in hydrodynamics of gas flow through anisotropic porous materials. E3S Web of Conferences. 2017; 19 ():3008.
Chicago/Turabian StyleGrzegorz WaŁowski; Gabriel Filipczak. 2017. "Klinkenberg effect in hydrodynamics of gas flow through anisotropic porous materials." E3S Web of Conferences 19, no. : 3008.
The results of experimental research upon the assessment of porous material anisotropy and its effect on gas permeability of porous materials with respect to the gas flow. The conducted research applied to natural materials with an anisotropic gap-porous structure and - for comparative purposes - to model materials such as coke, pumice and polyamide agglomerates. The research was conducted with the use of a special test stand that enables measuring the gas permeability with respect to three flow orientations compared with symmetric cubic-shaped samples. The research results show an explicit impact of the flow direction on the permeability of materials porous, which results from their anisotropic internal structures. The anisotropy coefficient and permeability effective coefficient of such materials was determined and an experimental evaluation of the value of this coefficient was conducted with respect to the gas stream and the total pressure drop across the porous deposit. The process of gas permeability was considered in the category of hydrodynamics of gas flow through porous deposits. It is important to broaden the knowledge of gas hydrodynamics assessment in porous media so far unrecognised for the development of a new generation of clean energy sources, especially in the context of biogas or raw gas production.
Grzegorz WaŁowski. Assessment of porous material anisotropy and its effect on gas permeability. E3S Web of Conferences 2017, 19, 03003 .
AMA StyleGrzegorz WaŁowski. Assessment of porous material anisotropy and its effect on gas permeability. E3S Web of Conferences. 2017; 19 ():03003.
Chicago/Turabian StyleGrzegorz WaŁowski. 2017. "Assessment of porous material anisotropy and its effect on gas permeability." E3S Web of Conferences 19, no. : 03003.
The results of hydrodynamic of gas flow through various type of porous material kind of coal-char are presented. With respect to hydrodynamics the studies have focused on the evaluation of the permeability of such materials as a resulting from the gas flow pressure drop. It allowed determining the permeability coefficient and the pressure drop coefficient, too. Due to anisotropic structure of carbonizers the examination were performed with respect to the flow direction, i.e. directivity permeability, as a result of three-dimensional orientation for each materials sample. The results of measurements indication strongly diversified hydrodynamic parameters for investigated types of materials, and comparison of test results leads to a conclusions that the main reason of this is clear of anisotropic structure of carbonizers. In order to obtain the wider description of microstructure process conditions as the hydrodynamic result of gas flow through porous materials, attempted to use the numerical method to assessment of this process. Numerical modeling indicated the concept of gas flow through porous a tortuous structure of microchannels and micropores, together forming a porous structure with a specific geometry – both an elementary unit constituting the porous layer-bed.
Grzegorz WaåOwski. Model of Gas Permeability Coefficient in Capture Hydrodynamics for Anisotropic Materials. Research & Reviews: Journal of Material Sciences 2017, 5, 1 .
AMA StyleGrzegorz WaåOwski. Model of Gas Permeability Coefficient in Capture Hydrodynamics for Anisotropic Materials. Research & Reviews: Journal of Material Sciences. 2017; 5 (2):1.
Chicago/Turabian StyleGrzegorz WaåOwski. 2017. "Model of Gas Permeability Coefficient in Capture Hydrodynamics for Anisotropic Materials." Research & Reviews: Journal of Material Sciences 5, no. 2: 1.
The results of experimental research concerning the assessment of the permeability of porous materials with respect to gas flow are presented in this paper. The conducted research applied to, among others, chars (acquired from the UCG thermal process) with an anisotropic gap-porous structure and - for comparative purposes - model materials such as pumice and polyamide agglomerates. The research was conducted with the use of a special test stand that enables the measuring of gas permeability with respect to three flow orientations compared with symmetric cubic-shaped samples. The research results show the explicit impact of the flow direction on the permeability of chars, which results from their anisotropic internal structures. The suitability of calculation methods employed to calculate the hydrodynamics of the gas flow through porous materials was also evaluated
Grzegorz Wałowski; Gabriel Filipczak. Assessment of process conditions associated with hydrodynamics of gas flow through materials with anisotropic internal structure. Journal of Sustainable Mining 2016, 15, 156 -169.
AMA StyleGrzegorz Wałowski, Gabriel Filipczak. Assessment of process conditions associated with hydrodynamics of gas flow through materials with anisotropic internal structure. Journal of Sustainable Mining. 2016; 15 (4):156-169.
Chicago/Turabian StyleGrzegorz Wałowski; Gabriel Filipczak. 2016. "Assessment of process conditions associated with hydrodynamics of gas flow through materials with anisotropic internal structure." Journal of Sustainable Mining 15, no. 4: 156-169.