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Design Analysis of Micro Gas Turbines in Closed Cycles
PublicationThe problems faced by designers of micro-turbines are connected with a very small volume flow rate of working media which leads to small blades’ height and high rotor speed. In the case of gas turbines this limitation can be overcome by the application of a closed cycle with very low pressure at the compressor inlet (lower than atmospheric pressure). In this way we may apply a micro gas turbine unit of accepted efficiency to work...
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Effect of Temperature and Nanoparticle Concentration on Free Convective Heat Transfer of Nanofluids
PublicationA theoretical analysis of the influence of temperature and nanoparticle concentration on free convection heat transfer from a horizontal tube immersed in an unbounded nanofluid was presented. The Nusselt (Nu) number and heat transfer coefficient were parameters of the intensity of the convective heat transfer. For free convection, the Nu number was a function of the Rayleigh (Ra) number and Prandtl (Pr) number. The Rayleigh (Ra)...
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Numerical methodology for evaluation the combustion and emissions characteristics on WLTP in the light duty dual-fuel diesel vehicle
PublicationThe worldwide aim of reducing environmental impact from internal combustion engines bring more and more stringent emission regulations. In 2017 by EU has been adopted new harmonized test procedure called WLTP. In general terms this test was designed for determining the levels of harmful emissions and fuel consumption of traditional and hybrid cars. This procedure contains specific driving scenarios which representing reallife driving...
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Experiments on compression ignition engine powered by nano-fuels
PublicationThe use of nanoparticles in fuels provides new opportunities for modification of fuel properties, which may affect the operational parameters of engines, in particular the efficiency and fuel consumption. The paper presents comparison of compression ignition engine performance fuelled with neat diesel and nano-diesel. Alumina (Al2O3) was used as nanoparticles. Surface-active substances, including Span 80 surfactant, as well as...
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The Staged Combustion of Meat-and-Bone Meal:The Characteristics of Conversion Sub-processes and Large-Scale Process Outputs
Publicationt Organic waste has been playing an increasingly important role in the energy market as those that may support the economies in pursuing towards decarbonization by increasing the share of renewables in the overall energy balance. In this group of alternative fuels, meat-and-bone meals being a post-production waste of the steadily developing meat industry, constitute a considerable proportion. Though they are rich in minerals, their...
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Heat transfer enhancement of modular thermal energy storage unit for reversible heat pump cooperation
PublicationThe following article presents experimental comparison research on a hexagonal shelland-tube latent thermal energy storage (TES). Such shape of a shell was deliberately chosen instead of a cylindrical one due to its high modularity and with intent for future applications in automobiles (EV and PHEV) air conditioning systems (HVAC). Two geometries of helical coils, acting as tubes, were studied in this article. One was a simple...
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Development of a spray-ejector condenser for the use in a negative CO2 emission gas power plant
PublicationOne promising solution for developing low-emission power technologies is using gaseous fuel combustion in pure oxygen when the exhaust gas mixture is composed of H2O and CO2, and where CO2 is separated after steam condensation. The paper presents the results of computational analyses providing to the Spray-Ejector Condenser (SEC) development, which is one of the crucial components of the negative CO2 gas power plant (nCO2PP) cycle...
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Review of Methods for Diagnosing the Degradation Process in Power Units Cooperating with Renewable Energy Sources Using Artificial Intelligence
PublicationThis work is based on a literature review (191). It mainly refers to two diagnostic methods based on artificial intelligence. This review presents new possibilities for using genetic algorithms (GAs) for diagnostic purposes in power plants transitioning to cooperation with renewable energy sources (RESs). The genetic method is rarely used directly in the modeling of thermal-flow analysis. However, this assignment proves that the...
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Experimental Investigation of the Performance of an Innovative Implantable Left Ventricular Assist Device—Proof of Concept
PublicationThis paper presents the results of experimental performance of an innovative left ventricular assist device working on a specially designed test stand. The introduced invention is mainly applied for supporting the heart in patients with end-stage heart failure accompanied by mitral valve regurgitation and pulmonary hypertension. Moreover, the developed device has the form of a flexible balloon forming an intracardiac inert gas-filled...
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Estimation of the Regenerative Braking Process Efficiency in Electric Vehicles
PublicationIn electric and hybrid vehicles, it is possible to recover energy from the braking process and reuse it to drive the vehicle using the batteries installed on-board. In the conditions of city traffic, the energy dissipated in the braking process constitutes a very large share of the total resistance to vehicle motion. Efficient use of the energy from the braking process enables a significant reduction of fuel and electricity consumption...
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Comparison of traditional district heating with low temperature district heating systems featuring organic Rankine cycle and heat pump
PublicationPaper presents a comparison between a traditional district heating system with conventional boilers as a source of heat and electricity purchases from power utilities and a low temperature DH system incorporating the CHP with organic Rankine Cycle providing electricity and local heat pump raising the temperature of the DH fluid to the required temperature in the dwelling, meaning that both heat and electricity are produced within...
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Method of reconstructing two-dimensional velocity fields on the basis of temperature field values measured with a thermal imaging camera
PublicationThis paper describes a novel numerical reconstruction procedure (NRP) of the velocity field during natural convective heat transfer from a two-sided, isothermal, heated vertical plate based only on the known temperature field obtained, e.g. with a thermal imaging camera. It has been demonstrated that with a knowledge of temperature distributions, the NRP enables the reconstruction of velocity fields by solving the Navier-Stokes...
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Modeling of Passive and Forced Convection Heat Transfer in Channels with Rib Turbulators
PublicationThe main goal of the research presented in this paper was the experimental and numerical analysis of heat enhancement and aerodynamic phenomena during air flow in a channel equipped with flow turbulators in the form of properly configured ribs. The use of ribs intensifies the heat transfer and at the same time increases not only the flow resistance but also the energy costs. Therefore, designing modern heat exchangers with optimal...
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Subcritical Thermodynamic Cycles with Organic Medium and Isothermal Expansion
PublicationThe efffciencies of the Organic Rankine Cycle (ORC) are not very high and only very seldom do they exceed 20%. The increase and optimization of initial parameters and certain modifications of the thermodynamic cycle make it possible to overcome these drawbacks. A new modified cycle has been described and analyzed in detail in the paper. Similarly to the Ericsson cycle for gas turbines, isothermal expansion in the turbine is suggested...
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Numerical analysis of vacuum drying of a porous body in the integrated domain
Publicationn the present study, the vacuum drying process of an apple slice is numerically modeled based on a control volume method. Transient two-dimensional Navier– Stokes, energy, moisture, and Luikov equations are solved by numerical coding (Fortran) to simulate the simultaneous heat and mass transfer in the ambient and apple slice, respectively. The privilege of using Luikov's model is that the capillary forces are considered, and a...
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Combined cold supply system for ship application based on low GWP refrigerants - Thermo-economic and ecological analyses
PublicationThe withdrawal of popular high-GWP refrigerants will significantly affect maritime industry. Refrigeration and air conditioning systems currently used on ships are not ready to fulfil future limitations. Therefore, there is a need for system, which will operate with low-GWP refrigerants and at the same time will be efficient and reliable in difficult environmental conditions. This paper explains the concept of a cold supply system,...
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Selected aspects of performance of organic Rankine cycles incorporated into bioenergy with carbon capture and storage using gasification of sewage sludge
PublicationThe study aims to investigate the application of the Organic Rankine Cycle (ORC) in the bioenergy with carbon capture and storage (BECCS) using gasification of sewage sludge. The tool used in the investigation is the Aspen Plus software with REFPROP property methods for calculating fluid properties. The reason for this study is that a detailed analysis of the proposed BECCS process flow diagram indicates that a certain amount of...
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Numerical analysis of the ostiomeatal complex aeration using the CFD method
PublicationWe aimed to analyse ostiomeatal complex (OMC) aeration using the computational fluid dynamics (CFD) method of simulation based on human craniofacial computed tomography (CT) scans. The analysis was based on CT images of 2 patients: one with normal nose anatomy and one with nasal septal deviation (NSD). The Reynolds-Average Simulation approach and turbulence model based on linear eddy viscosity supplemented with the two-equation...
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Challenges in operating and testing loop heat pipes in 500–700 K temperature ranges
PublicationThe potential applications of loop heat pipes (LHPs) are the nuclear power space systems, fuel cell thermal management systems, waste heat recovery systems, medium temperature electronic systems, medium temperature military systems, among others. Such applications usually operate in temperature ranges between 500–700 K, hence it is necessary to develop an LHP system that will meet this requirement. Such a thermal management device...
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Organic Rankine cycle turbogenerator cooling – Optimization of the generator water jacket heat exchange surface
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Comparative study of a combined heat and power plant retrofitted by CO2 capture during the combustion of syngas from sewage sludge gasification versus zero-emission combustion of hydrogen produced using renewables
PublicationWith ecological requirements aimed at limiting the production of CO2, it is necessary to produce all, or most of the energy from RES. During the transformation process, ecological and highly efficient combustion power plants will be needed. The classic cycle of combined heat and power (CCGT) with green improvements will continue to be one of the most suitable technologies for this task. This article presents the modernization of...
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Optimization of the distance between the vertical plates in the convective air heat exchanger
PublicationThis paper examines the influence of the distance between vertical plates on the intensity of free convective heat transfer along with the optimization of this distance. Experimental tests were carried out for one model channel of such an heat exchanger with widths , 0.085 and 0.18 m. This channel, open at the top and sides, was formed by two isothermal symmetrically heated parallel vertical plates of dimensions m and m. The influence...
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From fluid mechanics backgrounds to modern field theory
PublicationOur presentation keeps a historical line of reasoning, since we start from old concepts of fluid mechanics and finish on concepts of modern field theory. We want to show that some facts from the nature phenomena, which have firstly been discovered on the ground of fluid mechanics, were next incorporated into physics and later become the important pattern for whole mathematical physics. Especially, well-known continuum models, which...
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Slowly-closing valve behaviour during steam machine accelerated start-up
PublicationThe paper discusses the state of stress in a slowly-closing valve during accelerated start-up of a steam turbine. The valve is one of the first components affected by high temperature gradients and is a key element on which the power, efficiency and safety of the steam system depend. The authors calibrated the valve model based on experimental data and then performed extended Thermal-FSI analyses relative to experiment. The issue...
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Impact of Temperature and Nanoparticle Concentration on Turbulent Forced Convective Heat Transfer of Nanofluids
PublicationTheoretical analysis of the influence of nanoparticles and temperature on the average Nusselt (Nu) number and the average heat transfer coefficient (HTC) during the turbulent flow of nanofluid in a horizontal, round tube was carried out. The Nu number is a function of the Reynolds (Re) number and the Prandtl (Pr) number, which in turn are functions of the thermophysical properties of the liquid and the flow conditions. On the other...
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Innovative Implantable Left Ventricular Assist Device—Performance under Various Resistances and Operating Frequency Conditions
PublicationThis paper presents the operation of an innovative left ventricular assist device under various resistances and operating frequencies. The operating principle of the device is based on pulsatile blood flow, which is forced by a suction–discharge device pumping helium into a set of intra-cardiac balloons. In this way, the ejection fraction of the left ventricle is increased, and the mitral valve is additionally occluded. What is...
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Stirling engines - the state of technology development and computational models
PublicationStirling engines represent a technologically important solution in combined heat and power systems. Their use enables the achievement of over 90 percent efficiency in the management of the primary energy source with a very high durability of the device, mainly due to the lack of contact of the working gas with external factors and a very small number of mechanical components. The use of a Stirling engine may be equally important...
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Burnout Investigation of Small Diameter Tubes Immersed in Nanofluids
PublicationThis paper deals with research into pool boiling critical heat flux (CHF) of water–Al2O3, water–TiO2 and water–Cu nanofluids on horizontal stainless steel tubes. The experiments were conducted under atmospheric pressure. Nanoparticles were tested at concentrations of 0.001%, 0.01%, 0.1% and 1% by weight. Ultrasonic vibration was used in order to stabilize the dispersion of the nanoparticles. Although dispersants were not used to...
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Computational fluid dynamics simulation of heat transfer from densely packed gold nanoparticles to isotropic media
PublicationThis work aims to determine and compare heat generation and propagation of densely packed gold nanoparticles (Au NPs) induced by a resonant laser beam (532 nm) according to the Mie theory. The heat flux propagation is transferred into the materials, which here are: silica glass; soda-lime-silica glass; borosilicate glass; polymethyl methacrylate (PMMA); polycarbonate (PC); and polydimetylosiloxane (PDMS). This analysis aims to...
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A study of jet impingement cooling enhancement by concave and convex heat sink shape modifications
PublicationThe rising demand for efficient cooling technologies is a strong driver of extensive research in this area. This trend is particularly strong in turbines and microprocessors technology. Presented study is focused on the jet impingement cooling concept, which is used in various configurations for many years. The potential of the heat sink shape modification is not yet fully explored. Available literature suggests that average Nusselt...
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Revalorisation of the Szewalski’s concept of the law of varying the last-stage blade retraction in a gas-steam turbine
PublicationThe article presents the implementations of the free vortex law to the blade of the last stage of a gas-steam turbine. First, a thermodynamic analysis was carried out, determining the parameters at the inlet, then the number of stages of the high and low-pressure part of the turbine was constructed, together with the kinematics and velocity vectors for subsequent stages of the axial turbine. The last step of article was to take...
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Experimental investigation on heat pipes supported by soy wax and lauric acid for electronics cooling
PublicationThis paper presents an experimental study of heat pipes for electronics cooling that were supported by energy storage materials (i.e. phase change materials - PCMs) coated at the adiabatic section. The PCMs utilized included two materials, namely lauric acid and soy wax, the latter being considered as a more cost-effective alternative. The study focused on three different powers: 20 W, 25 W, and 30 W. Both heating, cooling, and...
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Energy conversion in systems-contained laser irradiated metallic nanoparticles - comparison of results from analytical solutions and numerical methods
PublicationThis work introduces the theoretical method of metallic nanoparticles’ (NPs’) heat and mass transfer where the particles are coated on a surface (base), together with considering the case wherein nanoparticles move freely in a pipe. In order to simulate the heat transfer, energy and radiative transfer equations are adjusted to the considered issue. NPs’ properties are determined following the nanofluidic theories, whereas absorption...
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Evaluation of the energy efficiency of electric vehicle drivetrains under urban operating conditions
PublicationIn electric vehicles, as in hybrids vehicles, a very important factor affecting the energy efficiency of the powertrain is the ability to use the regenerative braking energy. Depending on the settings available in electric vehicles, the driver can choose different modes of operation: switch off the regenerative braking mode altogether, select the intensity of regenerative braking, or leave the control system in automatic mode....
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The In-House Method of Manufacturing a Low-Cost Heat Pipe with Specified Thermophysical Properties and Geometry
PublicationVarious types of heat pipes are available to purchase off the shelf, from various manufacturers, but most of them have strictly defined geometry and technical parameters. However, when there is a need to use a heat pipe (HP) with an unusual size and shape or working conditions other than the standard ones, it becomes very costly to order them from manufacturers, especially in small quantities, and only a few producers are willing...
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Comparison of various flow maldistribution quantification methods in mini heat exchangers
PublicationThe aim of study is to compare various flow maldistribution quantification methods, using velocity, mass flow rate, pressure, and temperature. An experimentally validated numerical study has been prepared and a heat exchanger with 34 semi-circular channels with a diameter of 3.1 mm has been tested. The minichannels were heated from the bottom with a heat flux of 50, 60, 70, and 80 kW/m2. The cases for various inlet velocities of...
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Verification of the method of reconstructing convective velocity fields on the basis of temperature fields in vertical, differential and equally heated, open and closed channels
PublicationThis paper describes a method of reconstructing velocity fields, i.e. a numerical reconstruction procedure (NRP) that involves the numerical processing of experimentally measured temperature distributions in free convection heat transfer. The NRP consists in solving only the continuity and Navier–Stokes equations with an additional source term. This term is proportional to a known temperature (e.g. from a thermal imaging camera)...
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The efficiency of turbomachinery in the zero-and three-dimensional approaches
PublicationEfficiency of turbomachinery is usually defined using an isentropic process. This approach provides a reliable reference point only when pressure and temperature measurements are available, e.g. at the casing inlet and outlet. In the case of a single stage internal efficiency determination the reference point is difficult. Computational fluid dynamics allows for an exact calculation of values of losses occurring in a turbine...
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CO2 capture using steam ejector condenser under electro hydrodynamic actuator with non-condensable gas and cyclone separator: A numerical study
PublicationThe concept for condensation of steam and CO2 separation in a negative CO2 emission gas power plant involves the utilization of a steam ejector condenser (SEC) for direct-contact condensation of vapor with inert gas (CO2) on a spray of subcooled liquid, integrated with a separator to produce pure CO2. Due to the increasing diffusion resistance and reduced convective heat transfer between the steam and subcooled water phases...
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Maszyny hydrotechniczne Kanału Elbląskiego cz. 1.
PublicationHistoria ta zdarzyła się wiele lat temu. W czasach, gdy jeszcze na świecie nie było komputerów, elektryczności, silników spalinowych i tego wszystkiego bez czego teraz nie potrafimy żyć i egzystować. Wydawało by się, że tym bardziej ludzie żyjący wiele lad przed nami, nie mogli sobie poradzić z przeciwnościami natury, nie mając tych wszystkich dobrodziejstw techniki, którymi my tak łatwo na co dzień się posługujemy. Ale czy...
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Maszyny Hydrotechniczne Kanału Elblaskiego cz. 2.
PublicationPierwszy projekt kanału z 1827 roku, autorstwa Tajnego Radcy Budowlanego Severina z Kwidzyna, zakładał wyrównanie poziomów luster wody w jeziorach. Jezioro Jeziorak, koło Iławy, było największym jeziorem regionu, liczyło ponad 30 km długości, zatem uznano, że jego poziom wody będzie bazowym dla pozostałych jezior. Uznano również, że Miejscowość Miłomłyn, będzie głównym węzłem komunikacyjnym na kanale, stąd bowiem będą rozchodziły...
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Effect of Vascular Lumen Reduction on the Performance and Energy Consumption of an Innovative Implantable LVAD
PublicationThis paper presents the results of a study on the effect of vascular lumen reduction on the performance of an innovative implantable LVAD (left ventricular assist device). It details the pressures in the individual cardiac chambers as a function of device frequency. In addition, mass flow rates and energy consumption of the device are examined, varying with lumen reduction and operating frequency. While the lumen reduction of the...
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Flow Maps and Flow Patterns of R1233zd(E) in a Circular Minichannel at Low, Medium and High Values of Saturation Pressure
PublicationThere is a gap in knowledge regarding the flow pattern of low-boiling working fluids in the range of high saturation temperatures (above 120°C) and medium and high reduced pressures (0.5-0.9). Data are present in the literature for similar values of reduced pressures, but for lower values of saturation temperature. This is due to the existing refrigeration applications of these working fluids. At high values of reduced pressure,...
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Hybrid geothermal-fossil power cycle analysis in a Polish setting with a focus on off-design performance and CO2 emissions reductions
PublicationGrowing demand for electricity due to economic development contributes to increased greenhouse gas production, especially CO2. However, emissions can be limited by enhancing the efficiency of primary energy conversion, such as integrating geothermal energy into coal-fired power plants. Therefore, this paper proposes replacing conventional feed-water heaters with geothermal preheaters to create a hybridized system. This study was...
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Analiza techniczno-ekonomiczna zastosowania systemu magazynowania energii zasilanego z instalacji fotowoltaicznej
PublicationW artykule dokonano oceny celowości implementacji magazynu energii do instalacji fotowoltaicznej o mocy zainstalowanej 39,3 kW. W analizowanym przypadku prąd produkowany jest na potrzeby gospodarstwa sadowniczego oraz mieszkańców domu jednorodzinnego. Analiza, oparta na realnych danych rocznej eksploatacji systemu fotowoltaicznego, uwzględnia ilość wyprodukowanej energii nadwyżki energii przekazywanej do sieci i z niej pobieranej....
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Performance of cryogenic oxygen production unit with exhaust gas bleed for sewage sludge gasification and different oxygen purities
PublicationThe paper presents a thermodynamic analysis of the integration of a cryogenic air separation unit into a negative CO2 emission gas power plant. The power cycle utilizes sewage sludge as fuel so this system fits into the innovative idea of bioenergy with carbon capture and storage. A cryogenic air separation unit integrated with the power plant was simulated in professional plant engineering and thermodynamic process analysis software....
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Impacts of Using Exhaust Gas Recirculation and Various Amount of Dimethyl Ether Premixed Ratios on Combustion and Emissions on a Dual-Fuel Compression Ignition Engine
PublicationIn the presented research, the authors dealt with the specific properties of the combustion process of dimethyl ether (DME) in a combustion car (Volkswagen Golf IV) engine AJM 1.9 TDI PDE made by Volkswagen factory. Dimethyl ether is an alternative fuel produced most often from natural gas, which can be used in compression ignition engines as a single fuel or co-burned with diesel oil. This work describes the impacts of using exhaust...
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Ocena wpływu dawki DME na wybrane wskaźniki procesu spalania w dwupaliwowym silniku o zapłonie samoczynnym
PublicationPrzedmiotem rozprawy jest analiza wpływu różnej ilości odparowanego DME wprowadzonego do kolektora dolotowego na wybrane wskaźniki spalania DME/ON dla wielu punktów pracy, turbodoładowanego silnika o zapłonie samoczynnym. Jako punkty pracy silnika, wybrano punkty najbardziej reprezentujące cykl jazdy WLTP dla samochodu Volkswagen Golf IV. Analizę procesu współspalania przeprowadzono z wykorzystaniem danych pomiarowych, uzyskanych...
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Experimental Study of Polish Sausage Drying Kinetics and Contraction by Image Data Analysis
PublicationThe goal of this paper has been to add an experimental data set for drying a meat product and provide a comparison with well-established thin-layer drying models. This article presented experimental investigations on the convective drying of Polish sausage slices at a temperature of 40°C. Slices have been in the thickness of 3 to 8mm. Measurements of mass loss and size change were performed. The data have been presented in the...
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Experimental and numerical study of thermal and electrical potential of BIPV/T collector in the form of air-cooled photovoltaic roof tile
PublicationAmong renewable energy sources, Building-Integrated Photovoltaic/Thermal (BIPV/T) systems are gaining increasing interest. To improve their economic competitiveness, technologies that increase their efficiency are searched for. The paper is devoted to evaluating the impact of various air-cooling configurations on the thermal and electrical performance of a photovoltaic roof tile. A numerical model of the own experimental system...