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Tytuł:
Wstępna analiza parametrów termicznych zestawu szybowego wypełnionego materiałem fazowo zmiennym
Preliminary analysys of the thermal properties of glazing unit filled with phase change material
Autorzy:
Wieprzkowicz, A.
Heim, D.
Powiązania:
https://bibliotekanauki.pl/articles/362453.pdf
Data publikacji:
2017
Wydawca:
Instytut Fizyki Budowli Katarzyna i Piotr Klemm
Tematy:
promieniowanie słoneczne
przemiana fazowa
temperatury przemian
magazynowanie ciepła
dynamika cieplna
solar radiation
phase transformation
change point
heat storage
thermal dynamics
Opis:
W pracy przedstawiono wyniki analiz numerycznych dynamiki cieplnej wybranych rodzajów oszklenia modyfikowanych materiałem fazowo-zmiennym (MFZ). Analizy wykonano dla dwóch zestawów danych meteorologicznych, charakterystycznych dla klimatu umiarkowanego oraz podzwrotnikowego oraz trzech orientacji przegrody względem stron świata. W zależności od lokalizacji zdefiniowano 2 rozwiązania techniczne przegrody. Zaproponowano 3 kryteria determinujące żądane temperatury przemiany fazowej MFZ wypełniającego jedną z przestrzenni międzyszybowych. Na podstawie wyników analiz numerycznych wyznaczono wymagane temperatury oraz dobrano dostępne materiały z grupy parafin. Wybrane materiały stanowią niskotemperaturowe magazyny ciepła w zakresie temperatur przemiany 18-21°C w przypadku doboru dla okresu zimowego oraz 25-31°C (35°C dla Santiago) w przypadku analiz przeprowadzonych dla lata.
The paper presents results of numerical analysis of thermal dynamics of selected types of glazing modified with phase-change material (PCM). The analyzes were performed for two sets of meteorological data, typical for the moderate and subtropical climate, and the three orientations of façade. Depending on the location, two technical solutions were defined. Three criteria have been proposed to determine the most efficient phase transition temperature of PCM filling one of the window cavities. Based on the results of numerical analysis, the required temperatures were determined and materials from the paraffin group were selected. Selected materials are low temperature heat stores with a transition temperature of 18-21°C for winter season and 25-31°C (35°C for Santiago) for summer analyzes.
Źródło:
Fizyka Budowli w Teorii i Praktyce; 2017, T. 9, nr 1, 1; 39-44
1734-4891
Pojawia się w:
Fizyka Budowli w Teorii i Praktyce
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamika cieplna budynku wykonanego z elementów modyfikowanych MFZ
Thermal dynamics of the building constructed from elements modified by PCM
Autorzy:
Machniewicz, A.
Heim, D.
Powiązania:
https://bibliotekanauki.pl/articles/362619.pdf
Data publikacji:
2015
Wydawca:
Instytut Fizyki Budowli Katarzyna i Piotr Klemm
Tematy:
przegroda
pojemność cieplna
materiały fazowo zmienne
MFZ
dynamika cieplna
symulacja
partition
heat capacity
phase change materials
PCM
thermal dynamics
simulation
Opis:
W pracy przedstawiono wyniki analiz numerycznych historii zmian temperatury w pomieszczeniu o zróżnicowanej konstrukcji przegrody zewnętrznej. Przeanalizowano cztery przypadki o różnie zdefiniowanej pojemności cieplnej oraz zdolności magazynowania ciepła utajonego. Do analizy wybrano cztery okresy trzydziestu dni, każdy rozpoczynający się w dniu o założonej, charakterystycznej temperaturze zewnętrznej, determinującej chwilową moc strat ciepła przez analizowaną przegrodę. Celem pracy było określenie efektu i potencjału wykorzystania elementów modyfikowanych Materiałami Fazowo Zmiennymi w celu zwiększenia pojemności cieplnej obudowy oraz stabilizacji temperatury w pomieszczeniu o niekontrolowanych parametrach środowiska wewnętrznego. Parametrami poddanymi analizie były chwilowe różnice temperatury w pomieszczeniu w poszczególnych przypadkach oraz czas po którym dana temperatura została osiągnięta. Na podstawie otrzymanych wyników można stwierdzić, że modyfikacja konstrukcji lekkiej za pomocą MFZ może przyczynić się do uzyskania okresowych (do 4 dni) charakterystyk termicznych podobnych jak w przypadku zastosowania konstrukcji masywnej.
The paper presents the results of numerical analyses of the rooms varied by the structure of the outer partition. Four cases of differently defined heat capacity and latent heat storage were analyzed. Simulations were performed for four 30-days periods, starting on the day with assumed, characteristic external temperature, which determined the instantaneous power of heat exchange through the analyzed partition. The aim of the study was to describe the potential of application of elements modified by phase change materials (PCM) and define the effect of its application on the increase of the heat capacity and stabilization of room temperature under uncontrolled parameters of the internal environment. The parameters analyzed were temporary differences of room temperature and the time after which the temperature has been reached (in comparison to other cases). Based on these results it can be concluded that the modification of the light structure with PCM can contribute to a thermal effects similar to those in the case of the use of massive structures.
Źródło:
Fizyka Budowli w Teorii i Praktyce; 2015, T. 7, nr 2, 2; 45-50
1734-4891
Pojawia się w:
Fizyka Budowli w Teorii i Praktyce
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Podstawy uproszczonej metody godzinowej obliczania ilości ciepła do ogrzewania i chłodzenia budynków
Instructions for camera- ready papers
Autorzy:
Narowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/362376.pdf
Data publikacji:
2008
Wydawca:
Instytut Fizyki Budowli Katarzyna i Piotr Klemm
Tematy:
fizyka budowli
dynamika cieplna
model 5R1C
metoda godzinowa
świadectwa energetyczne
building physics
thermal dynamics
hourly method
energy certificates
Opis:
W artykule przedstawiono uproszczoną metodę wyznaczania ilości ciepła do ogrzewania i chłodzenia budynku zbudowaną w oparciu o analogię elektryczną modelu skupionej pojemności cieplnej. Podstawą modelu nieustalonego procesu wymiany ciepła pomiędzy budynkiem i jego otoczeniem jest układ 5R1C, którego zachowanie się opisuje równanie różniczkowe zwyczajne. W pracy przedstawiono metodę rozwiązania równania tego modelu przy zmiennych warunkach brzegowych zmodyfikowaną metodą Eulera, która wraz z metodą superpozycji układu liniowego w pojedynczej chwili czasu prowadzi do równań uproszczonej godzinowej metody dynamiki cieplnej budynku.
This paper presents the basis of 5R1C model of building heat exchange with the outer environment. The lumped capacitance method used for whole building is utilized to get equations of simply 5RIC hour method. This method can be used for calculation of heat and cool demand for building and is adopted in Poland for determining energy performance class for nonrcsidential buildings as required by HU Energy Performance Building Directive. The article was written due to the support of STEP Project PL 0077 financed by a grant from Iceland. Liechtenstein and Norway through the EEA Financial Mechanism and the Norwegian Financial Mechanism
Źródło:
Fizyka Budowli w Teorii i Praktyce; 2008, T. 3; 77-84
1734-4891
Pojawia się w:
Fizyka Budowli w Teorii i Praktyce
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal oil biomass boiler dynamics as a part of the micro-CHP ORC plant
Autorzy:
Turzyński, T.
Żywica, G.
Powiązania:
https://bibliotekanauki.pl/articles/175454.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
CHP
boiler
dynamics
ORC
micro-turbine
thermal oil
Opis:
The aim of the paper is to present the results of experimental research conducted on two helical coil biomass boilers with oil heatingagent, which are acentral unitsof co generative micro powerplant designed and built in IFFM in Gdańsk. Experimental data served as a source for defining the interdependencies governing the dynamics of the micro-CHP as a whole. Furthermore, during the research the authors came across a few possible modifications to the construction that may yet improve the device.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2017, 138; 3-11
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Introduction to non-linear Thermal-FSI on the example of transient load of a thin-walled container
Autorzy:
Kraszewski, B.
Powiązania:
https://bibliotekanauki.pl/articles/1818166.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
thermal-FSI
CFD
computational fluid dynamics
CSD
computational solid dynamics
non-linear mechanics
Opis:
This paper presents the problems associated with the transient thermal load of structures exhibiting a non-linear relationship between load and strain. The mathematical model required to comprehensively describe the relationship between fluid and solid has been shown from different perspectives. In addition, the Newton-Raphson method has been referred to as a way of solving nonlinear equations. The article also presents the assumptions and results of numerical analysis of thin-walled container thermally loaded by contact with hot water. The conclusions drawn emphasize the importance of Thermal-FSI tools, especially in the power engineering sector.
Źródło:
Zeszyty Energetyczne; 2018, 5; 1--13
2658-0799
Pojawia się w:
Zeszyty Energetyczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new cast-resin transformer thermal model based on recurrent neural networks
Autorzy:
Azizian, D.
Bigdeli, M.
Powiązania:
https://bibliotekanauki.pl/articles/141202.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cast-resin transformer
dynamics
recurrent neural networks
thermal modeling
Opis:
Thermal modeling in the transient condition is very important for cast-resin dry-type transformers. In the present research, two novel dynamic thermal models have been introduced for the cast-resin dry-type transformer. These models are based on two artificial neural networks: the Elman recurrent networks (ELRN) and the nonlinear autoregressive model process with exogenous input (NARX). Using the experimental data, the introduced neural network thermal models have been trained. By selecting a typical transformer, the trained thermal models are validated using additional experimental results and the traditional thermal models. It is shown that the introduced neural network based thermal models have a good performance in temperature prediction of the winding and the cooling air in the cast-resin dry-type transformer. The introduced thermal models are more accurate for the temperature analysis of this transformer and they will be trained easily. Finally, the trained and validated thermal models are employed to evaluate the life-time and the reliability of a typical cast-resin dry-type transformer.
Źródło:
Archives of Electrical Engineering; 2017, 66, 1; 17-28
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Passive cooling through the atmospheric window for vehicle temperature control
Autorzy:
Khan, Umara
Zevenhoven, Ron
Powiązania:
https://bibliotekanauki.pl/articles/1955001.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
thermal radiation
passive cooling
vehicle skylight
greenhouse effect
computational fluid dynamics
Opis:
One of the most energy-intensive activities for a vehicle is space air conditioning, for either cooling or heating. Considerable energy savings can be achieved if this can be decoupled from the use of fuel or electricity. This study analyzes the opportunities and effectiveness of deploying the concept of passive cooling through the atmospheric window (i.e. the 8– 14 nm wavelength range where the atmosphere is transparent for thermal radiation) for vehicle temperature control. Recent work at our institute has resulted in a skylight (roof window) design for passive cooling of building space. This should be applicable to vehicles as well, using the same materials and design concept. An overall cooling effect is obtained if outgoing (long wavelength greater than 4 nm) thermal radiation is stronger than the incoming (short wavelength less than 4 nm) thermal radiation. Of particular interest is to quantify the passive cooling of a vehicle parked under direct/indirect sunlight equipped with a small skylight, designed based on earlier designs for buildings. The work involved simulations using commercial computational fluid dynamics software implementing (where possible) wavelengthdependency of thermal radiation properties of materials involved. The findings show that by the use of passive cooling, a temperature difference of up to 7–8 K is obtained with an internal gas flow rate of 0.7 cm/s inside the skylight. A passive cooling effect of almost 27 W/m2 is attainable for summer season in Finland. Comparison of results from Ansys Fluent and COMSOL models shows differences up to about 10 W/m2 in the estimations.
Źródło:
Archives of Thermodynamics; 2021, 42, 3; 25--44
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Molecular dynamics simulations of thermal conductivity of penta-graphene
Autorzy:
Muna, Isyna
Winczewski, Szymon
Powiązania:
https://bibliotekanauki.pl/articles/1954605.pdf
Data publikacji:
2020
Wydawca:
Politechnika Gdańska
Tematy:
penta-graphene
thermal conductivity
molecular dynamics
grafen
przewodnictwo cieplne
dynamika molekularna
Opis:
The thermal conductivity of penta-graphene (PG), a new two dimensional carbon allotrope and its dependence on temperature, strain, and direction are studied in this paper. The thermal conductivity of PG is investigated using a non-equilibrium molecular dynamics simulation (NEMD) with the Two Region Method by applying the optimized Tersoff interatomic potential. Our study shows that the thermal conductivity of PG (determined for the [100] direction) at the room temperature of 300 K is about 18.7 W/(m K), which is much lower than the thermal conductivity of graphene. As the temperature increases, the thermal conductivity of PG is decreasing because, unlike graphene, PG has lower phonon group velocities and few collective phonon excitations. The obtained dependence of the thermal conductivity on the temperature can be described as κ ∼ T −0.32. For the [110] direction the thermal conductivity at the room temperature of 300 K is very similar: about 17.8 W/(m K). In this case, the temperature dependence follows the κ ∼ T −0.3 relation. Our investigations reveal that the thermal conductivity of PG is isotropic, meaning that heat transport behavior is independent of the heat flow direction. Our results indicate that the thermal conductivity of PG depends in an interesting way on the applied strain: nonmonotonic up-and-down behavior is observed. The thermal conductivity increases between strains from 0% up to 12.5%, and it decreases above a strain of 12.5%. Our investigation highlights the fascinating thermal transport properties of penta-graphene. The ultra-low thermal conductivity, the decreasing thermal conductivity with the increasing temperature, and the ultra-high mechanical strength of PG show that PG possesses a great potential in thermoelectric and nanomechanics applications. We hope that these findings, made by means of simulations, will become a bridge to inspire and encourage the experimental works, especially in the synthesis of PG.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2020, 24, 3; 191-220
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studying the Efficiency of Treatment Model Mixtures of Petroleum Products with the Modified Sorbent Made of Ash-and-Slag During Dynamic Sorption
Autorzy:
Korotkova, Tatyana Germanovna
Bushumov, Svyatoslav Andreevich
Ksandopulo, Svetlana Yurevna
Solonnikova, Nataliya Vladimirovna
Powiązania:
https://bibliotekanauki.pl/articles/123373.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
ash and slag
thermal power plant
sorbent
sorption dynamics
efficiency
petroleum products
extraction
Opis:
Experimental studies on the dynamic sorption of model mixtures containing petroleum products were performed. The subject of the study was the modified sorbent from the ash-and-slag wastes accumulated in the ash dump of the Novocherkassk State District Power Plant (SDPP) (Russia, Novocherkassk, Rostov Region), obtained using the method of ash removal. The quantity of the sorbent for each model solution was fixed at 5.0 g. The model solutions in the amount of 1 dm3 were passed through a column filled with the modified sorbent at constant filtration rate w = const with filtrate takeout of 0.1 dm3/min. The pH value of the solution, which is advisable for extracting petroleum products, was determined experimentally. For this purpose, the model solutions, containing 100 mg/dm3 of petroleum products with pH = 1.65, 4.01, 6.86, 8.12, 9.18, and 11.34, were prepared. The optimum pH value of the solution was considered pH = 7.5. The content of petroleum products in the filtrate in all experiments was determined using IR spectrometry. The working range of water pollution with petroleum products was determined on a series of model solutions containing petroleum products in the range between 0.5 and 10 mg/dm3 with the increment of 0.5, between 10 and 100 mg/dm3 with the increment of 10, and between 100 and 1,000 mg/dm3 with the increment of 100. The maximum extraction of petroleum products from the solution was 88.23%. The applicability of the Henry’s law to the range of petroleum products concentrations in the filtrate of 50 mg/dm3 was confirmed. The adsorption equilibrium constant (Henry’s law constant) was determined experimentally. The effect of the natural freshwater matrix on the degree of petroleum products extraction was studied; no significant effect on petroleum products sorption was found. A conclusion was made that the sorbent can ensure the efficiency of water purifying from petroleum products of no less than 85% in the range of pollution between 5 and 300 mg/dm3.
Źródło:
Journal of Ecological Engineering; 2019, 20, 11; 202-209
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulation and improvement of combustor structure in 3D printed sand recycling system
Autorzy:
Gao, Xiao
Lei, Mao
Xu, Weiwei
Powiązania:
https://bibliotekanauki.pl/articles/27315668.pdf
Data publikacji:
2023
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
3D printing
CPFD
Computional Particle Fluid Dynamics
thermal reclamation of used sand
Opis:
In this paper, a new combustor with an output of 5 t/h is designed based on a computational particle fluid dynamics (CPFD) model. The flow field simulation is combined with the combustion simulation to analyze the internal two-phase flow, temperature field, and combustion products. The combustor structure was optimized. The simulation results show that the recovery efficiency of the waste sand and the energy utilization of the combustor can be improved under the original structure. The sand bed has a significant effect on flow field characteristics. The increase in particle temperature in the combustor increases the efficiency of waste sand recovery by increasing the height of the sand bed by 50 mm. The utilization rate of natural gas is increased and the economic efficiency is improved. The feasibility of the CPFD method can simulate the flow field characteristics inside the combustor very effectively.
Źródło:
Polish Journal of Chemical Technology; 2023, 25, 4; 19--27
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Expansion of Explosive Molecular Crystals: Anisotropy and Molecular Stacking
Autorzy:
Qian, W.
Zhang, C.
Xiong, Y.
Zong, H.
Zhang, W.
Shu, Y.
Powiązania:
https://bibliotekanauki.pl/articles/358262.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
energetic material
anisotropic thermal expansion
molecular stacking
molecular dynamics simulation
density functional theory method
Opis:
Molecular dynamics simulations of three typical explosive crystals, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), 1,1-diamino-2,2- dinitroethene (FOX-7) and 1,3,5-triamino-2,4,6-trinitrobenzene (TATB), were carried out under NPT ensemble and selected force field. The equilibrium structures at elevated temperatures were obtained, which show that the stacking behaviour of the molecules does not change with temperature. The coefficient of thermal expansion (CTE) values were calculated by linear fitting methods, and the results show that the CTE values are close to the experimental results and are anisotropic. The total energies of the cells expanding along each single crystallographic axis were calculated by the periodic density functional theory method, indicating that the energy change rates are anisotropic, and correlation equations of the energy change vs. CTE values were established. The essence of the anisotropy of the explosive crystal’s thermal expansion was compared and elucidated.
Źródło:
Central European Journal of Energetic Materials; 2014, 11, 1; 59-81
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal analysis of Double Stator Switched Reluctance Machine (DSSRM) with and without a squirrel cage rotor
Autorzy:
Abbasian, M.
Jalali, H.
Powiązania:
https://bibliotekanauki.pl/articles/140844.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Computational Fluid Dynamics (CFD)
Finite Element Method (FEM)
squirrel cage
double stator
switched reluctance machine
thermal analysis
Opis:
Double Stator Switched Reluctance Machine (DSSRM) is a novel switched reluctance machine with limited information about its heat distribution and dissipation. This paper presents a two dimensional (2-D) thermal analysis of Double Stator Switched Reluctance Machine (DSSRM) to observe actual heat distribution in the parts of the machine, using Finite Element Method (FEM). Two topologies for the rotor of DSSRM are considered, Non-Squirrel Cage Double Stator Switched Reluctance Machine (NSCDSSRM) and Squirrel Cage Double Stator Switched Reluctance Machine (SC-DSSRM). The heat distribution of these two topologies is analyzed, using Computational Fluid Dynamics (CFD). Finally the results are presented and compared.
Źródło:
Archives of Electrical Engineering; 2017, 66, 1; 189-198
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of phonon relaxation time for silicon by means of using the velocity autocorrelation function of atoms in molecular dynamics
Autorzy:
Andriyevsky, Bohdan
Maliński, M.
Buryło, Ł.
Stadnyk, V. Y.
Romanuk, M. O.
Piekarski, J.
Andriyevska, L.
Powiązania:
https://bibliotekanauki.pl/articles/201222.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
silicon
molecular dynamics
relaxation time of the velocity autocorrelation function
coefficient of thermal diffusivity
krzem
dynamika molekularna
Opis:
Results of the ab initio molecular dynamics calculations of silicon crystals are presented by means of analysis of the velocity autocorrelation function and determination of mean phonon relaxation time. The mean phonon relaxation time is crucial for prediction of the phonon-associated coefficient of thermal conductivity of materials. A clear correlation between the velocity autocorrelation function relaxation time and the coefficient of thermal diffusivity has been found. The analysis of the results obtained has indicated a decrease of the velocity autocorrelation function relaxation time t with increase of temperature. The method proposed may be used to estimate the coefficient of ther-mal diffusivity and thermal conductivity of the materials based on silicon and of other wide-bandgap semiconductors. The correlation between kinetic energy fluctuations and relaxation time of the velocity autocorrelation function has been calculated with the relatively high coefficient of determination R2 = 0.9396. The correlation obtained and the corresponding approach substantiate the use of kinetic energy fluctuations for the calculation of values related to heat conductivity in silicon-based semiconductors (coefficients of thermal conductivity and diffusivity).
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 3; 651-656
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhancement of thermal efficiency of nanofluid flows in a flat solar collector using CFD
Autorzy:
Zarda, Falah
Hussein, Adnan Mohammed
Danook, Suad H.
Mohamad, Barhm
Powiązania:
https://bibliotekanauki.pl/articles/2146747.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
solar collector flat-plate
diamond/H2O nanofluids
thermal performance
computational fluid dynamics
płaski kolektor słoneczny
właściwości cieplne
numeryczna mechanika płynów
Opis:
Flat plate solar collector (FPSC) is popular for their low cost, simplicity, and ease of installation and operation. In this work, FPSC thermal performance was analyzed. It's compared to diamond/H2O nanofluids. The volume percentage and kind of nanoparticles are analyzed numerically that validation with experimental data available in the literature. The hot climate of Iraq is employed to approximate the model. The numerical study is performed by using ANSYS/FLUENT software to simulate the case study of problem. Due to less solar intensity after midday, temperatures reduction. The greatest collector thermal efficiency is 68.90% with 1% ND/water nanofluid, a 12.2% increase over pure water. The efficiency of 1% nanofluid is better than other concentrations because of a change in physical properties and an increase in thermal conductivity. Since the intensity of radiation affects the outlet temperature from the solar collector and there is a direct link between them, this increases the efficiency of the solar collector, especially around 12:30 pm at the optimum efficiency.
Źródło:
Diagnostyka; 2022, 23, 4; art. no. 2022411
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical investigation into the effect of direct fuel injection on thermal stratification in HCCI engine
Autorzy:
Gęca, M.
Hunicz, J.
Jaworski, P.
Powiązania:
https://bibliotekanauki.pl/articles/133917.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Naukowe Silników Spalinowych
Tematy:
homogeneous charge compression ignition
HCCI
direct injection
thermal stratification
computational fluid dynamics
CFD
silnik wysokoprężny o spalaniu homogenicznym
wtrysk bezpośredni
stratyfikacja termiczna
obliczeniowa mechanika płynów
Opis:
Despite the fact that HCCI engines are distinguished by mixture homogeneity, some degree of stratification always appears inside a combustion chamber. It is especially applied to residual effect engines utilizing negative valve overlap. Mixture stratification is a result of the imperfect mixing of fresh air with trapped residuals. Direct fuel injection introduces stratification as well, due to fuel vaporization. As a consequence, the temperature within the combustion chamber is uneven. Thermal stratification affects auto-ignition timing and combustion evolution in a high extent. The purpose of this study was to evaluate a degree of thermal stratification in HCCI engine utilizing negative valve overlap. Investigations were performed using three-dimensional CFD model of the combustion system, made by using AVL FIRE software. Simulations were realized for various timings of fuel injection into the cylinder. It was found that fuel injection timing had a significant effect on the thermal stratification and resulting auto-ignition timing.
Źródło:
Combustion Engines; 2017, 56, 2; 137-140
2300-9896
2658-1442
Pojawia się w:
Combustion Engines
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 21

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