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    Wyświetlanie 1-9 z 9
    Tytuł:
    Optimization of geometric and flow parameters of solar air heater roughened with artificial roughness by Taguchi method
    Autorzy:
    Sahu, Mukesh Kumar
    Mishra, Shivam
    Kumar, Avinash
    Powiązania:
    https://bibliotekanauki.pl/articles/27312207.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    roughness
    nusselt number
    friction factor
    Taguchi method
    optimization
    Opis:
    The paper presents the investigation of the optimum design parameters of a solar air heater (SAH) having wire ribs as artificial roughness by using the Taguchi method. The solar air heater has arc shape roughness geometry with apex upstream flow on the absorber plate. The objective of this paper is to obtain a set of parameters that deliver maximum thermo-hydraulic performance. For this objective, a new parameter the thermo-hydraulic improvement parameter (ηTHIP), has been introduced. For the present analysis, the effects of Reynolds number (Re), relative roughness pitch (P/e), angle of attack (α), and relative roughness height (e/Dh), denoted by A, B, C, and D, respectively, have been considered. An (L18 = 61 · 3 2 ) orthogonal array (OA) was chosen as an experimental plan for applying the Taguchi method. The set of control factors for the solar air heater SAH which delivers the maximum Nusselt number (Nu), and minimum friction factor (fr) – are A6B2C2, and A1B1C3 respectively. To obtain the maximum THIP the experimental set-up requires only one single run using the parameter A6B2C2, hence there is no need to run it all 54 times.
    Źródło:
    Archives of Thermodynamics; 2023, 44, 3; 3--33
    1231-0956
    2083-6023
    Pojawia się w:
    Archives of Thermodynamics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical modeling of heat transfer in Al2O3/H2O nanofluid flowing through a Bessel-like converging pipe
    Autorzy:
    Iweka, Chukwuka S.
    Fadodun, Olatomide G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1845460.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    nanofluid
    Nusselt number
    response surface methodology
    Reynolds number
    convergence
    index
    Opis:
    This paper studies hydrodynamic and heat transfer performance of Al2O3/H2O nanofluid flowing through a Bessel-like converging pipe in laminar flow regime using the computational fluid dynamic approach. A parametric study was carried out on the effect of Reynolds number (300– 1200), convergence index (0-3) and nanoparticle concentration (0–3%) on the both hydrodynamic and thermal fields. The results showed the pressure drop profile along the axial length of the converging pipes is parabolic compared to the downward straight profile obtained in a straight pipe. Furthermore, an increase in convergence index, Reynolds number and nanoparticle concentration were found to enhance convective heat transfer performance. Also, a new empirical model was developed to estimates the average Nusselt number as a function of aforementioned variables. Finally, the result of the thermohydraulic performance evaluation criterion showed that the usage of Bessel-like converging pipes is advantageous at a low Reynolds number.
    Źródło:
    Archives of Thermodynamics; 2021, 42, 2; 121-153
    1231-0956
    2083-6023
    Pojawia się w:
    Archives of Thermodynamics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical modeling of heat transfer in Al2O3/H2O nanofluid flowing through a Bessel-like converging pipe
    Autorzy:
    Iweka, Chukwuka S.
    Fadodun, Olatomide G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1845485.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    nanofluid
    nusselt number
    response surface methodology
    Reynolds number
    convergence
    index
    Opis:
    This paper studies hydrodynamic and heat transfer performance of Al2O3/H2O nanofluid flowing through a Bessel-like converging pipe in laminar flow regime using the computational fluid dynamic approach. A parametric study was carried out on the effect of Reynolds number (300– 1200), convergence index (0-3) and nanoparticle concentration (0–3%) on the both hydrodynamic and thermal fields. The results showed the pressure drop profile along the axial length of the converging pipes is parabolic compared to the downward straight profile obtained in a straight pipe. Furthermore, an increase in convergence index, Reynolds number and nanoparticle concentration were found to enhance convective heat transfer performance. Also, a new empirical model was developed to estimates the average Nusselt number as a function of aforementioned variables. Finally, the result of the thermohydraulic performance evaluation criterion showed that the usage of Bessel-like converging pipes is advantageous at a low Reynolds number.
    Źródło:
    Archives of Thermodynamics; 2021, 42, 2; 121-153
    1231-0956
    2083-6023
    Pojawia się w:
    Archives of Thermodynamics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical investigation and sensitivity analysis of turbulent heat transfer and pressure drop of Al2O3/H2O nanofluid in straight pipe using response surface methodology
    Autorzy:
    Fadodun, Olatomide G.
    Amosun, Adebimpe A.
    Salau, Ayodeji O.
    Olaloye, David O.
    Ogundeji, Johnson A.
    Ibitoye, Francis I.
    Balogun, Fatai A.
    Powiązania:
    https://bibliotekanauki.pl/articles/239962.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    nusselt number
    Reynolds number
    pressure drop
    response surface methodology
    nanofluid
    single phase flow
    Opis:
    In this paper, investigation of the effect of Reynolds number, nanoparticle volume ratio, nanoparticle diameter and entrance temperature on the convective heat transfer and pressure drop of Al2O3/H2O nanofluid in turbulent flow through a straight pipe was carried out. The study employed a computational fluid dynamic approach using single-phase model and response surface methodology for the design of experiment. The Reynolds average Navier-Stokes equations and energy equation were solved using k-ε turbulent model. The central composite design method was used for the response-surface-methodology. Based on the number of variables and levels, the condition of 30 runs was defined and 30 simulations were performed. New models to evaluate the mean Nusselt number and pressure drop were obtained. Also, the result showed that all the four input variables are statistically significant to the pressure drop while three out of them are significant to the Nusslet number. Furthermore, sensitivity analysis carried out showed that the Reynolds number and volume fraction have a positive sensitivity to both the mean Nusselt number, and pressure drop, while the entrance temperature has negative sensitivities to both.
    Źródło:
    Archives of Thermodynamics; 2020, 41, 1; 3-30
    1231-0956
    2083-6023
    Pojawia się w:
    Archives of Thermodynamics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The effect of reduced heat transfer in a micropolar fluid in natural convection
    Autorzy:
    Rup, K.
    Dróżdż, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/240722.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    micropolar fluid
    microrotation
    boundary layer theory
    Local Nusselt number
    teoria warstwy przyściennej
    Liczba Nusselta
    Opis:
    This paper presents the numerical solution to the unsteady natural convection problem in micropolar fluid in the vicinity of a vertical plate, heat flux of which rises suddenly at a given moment. In order to solve this problem the method of finite differences was applied. The numerical results have been presented for a range of values of the dimensionless material properties and fluid Prandtl number. The analysis of the results shows that the intensity of the heat transfer in micropolar fluid is lower compared to the Newtonian fluid.
    Źródło:
    Archives of Thermodynamics; 2013, 34, 3; 45-59
    1231-0956
    2083-6023
    Pojawia się w:
    Archives of Thermodynamics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On numerical modelling of heat transfer and fluid flow in a scraped surface heat exchanger
    Autorzy:
    Błasiak, P.
    Gnutek, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/240070.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    scraped surface heat exchanger
    nusselt number
    thermal boundary layer
    wymiennik ciepła
    liczby Nusselta
    termiczna warstwa przyścienna
    Opis:
    Steady state two-dimensional numerical simulation of laminar heat transfer and fluid flow in a scraped surface heat exchanger (SSHE) is presented. Typical SSHE consists of a stator, rotating shaft and scraping blades. Due to symmetry only a quarter of the heat exchanger is modelled. Governing equations for transport of mass, momentum and energy are discretised and solved with the use of commercial CFD code. The results are presented in a nondimensional form for velocity, pressure and temperature distributions. Local and averaged Nusselt number along the stator wall are calculated and depicted in graphs. It was found that the thirty fold increase of the cReynolds number, leads to heat transfer enhancement rate by three times.
    Źródło:
    Archives of Thermodynamics; 2014, 35, 3; 251-264
    1231-0956
    2083-6023
    Pojawia się w:
    Archives of Thermodynamics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Heat transfer and friction factor correlation for inclined spherical ball roughened solar air heater
    Autorzy:
    Murmu, Ramesh
    Kumar, Parmanand
    Singh, Hari N.
    Powiązania:
    https://bibliotekanauki.pl/articles/240765.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    renewable energy
    spherical ball
    relative roughness pitch
    relative roughness height
    nusselt number
    friction factor
    angle of attack
    Opis:
    Flow mechanism under roughened solar air heater is quite complex. This paper is an effort towards determining the governing equations for heat transfer and friction factor for inclined spherical balls roughened ducts. With the availability of these equations, it is easier to predict the thermal and thermohydraulic performance of such roughened solar air heaters. The governing equations are derived based on the experimental data generated under actual outdoor condition at the test rig designed and fabricated at the terrace of the Mechanical Engineering Department, the National Institute of Technology Jamshedpur in India, in terms of roughness and flow parameters. Maximum augmentation in Nusselt number and friction factor for varying relative roughness pitch, relative roughness height, spherical ball height to diameter ratio, and angle of attack was respectively found to be of the order of 2.1 to 3.54 times, 1.87 to 3.21 times, 2.89 to 3.27 times and 1.74 to 3.56 times for Nusselt number and 0.84 to 1.79 times, 1.46 to 1.91 times, 1.67 to 2.34 times and 1.21 to 2.67 times for friction factor in comparison to non-roughened duct. The optimum roughness parameters under present investigation have been found.
    Źródło:
    Archives of Thermodynamics; 2020, 41, 2; 3-34
    1231-0956
    2083-6023
    Pojawia się w:
    Archives of Thermodynamics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Augmentation in heat transfer and friction of three sides over one side dimple roughened solar duct
    Autorzy:
    Kumar, Vikash
    Powiązania:
    https://bibliotekanauki.pl/articles/240256.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    dimple roughened
    relative roughness pitch
    relative roughness height
    dimple depth to diameter ratio
    nusselt number
    friction factor
    Opis:
    Providing roughness is an effective method to heat fluids to high temperature. Present paper make use of concave dimple roughness on one and three sides of roughened ducts aimed at determining rise in heat transfer and friction of three sides over one side roughened duct. Three sides roughened duct produces high heat transfer compared to one side roughened. Results are shown as a rise in Nusselt number and friction factor of three sides over one side roughened duct. Experimental investigation was conducted under actual outdoor condition at National Institute of Technology Jamshedpur, India to test various sets of roughened collectors. Roughness parameter varied as relative roughness pitch 8–15, relative roughness height 0.018–0.045, dimple depth to diameter ratio 1–2, Reynolds number 2500– 13500 at fixed aspect ratio (width/hight) 8. Highest enhancement in Nusselt number for varying relative roughness pitch, height, and diameter ratio was respectively found as 2.6 to 3.55 times, 1.91 to 3.42 times and 3.09 to 3.94 times compared to one side dimple roughened duct. Highest rise in friction for three sides over one side roughened duct for these varying parameters was respectively found as 1.62 to 2.79 times, 1.52 to 2.34 times and 2.21 to 2.56 times. To visualize the effect of roughness parameter on heat transfer and friction factor, variation in Nusselt number and friction factor for varying roughness parameters with Reynolds number is shown.
    Źródło:
    Archives of Thermodynamics; 2020, 41, 3; 57-89
    1231-0956
    2083-6023
    Pojawia się w:
    Archives of Thermodynamics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Thermal and hydraulic phenomena in boundary layer of minijets impingement on curved surfaces
    Autorzy:
    Kura, T.
    Fornalik-Wajs, E.
    Wajs, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/240656.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    jet impingement
    minijets array
    boundary layer
    entropy generation
    Nusselt number
    uderzenie
    strumień
    warstwa przyścienna
    generowanie entropii
    liczby Nusselta
    Opis:
    Presented work considers flow and thermal phenomena occurring during the single minijet impingement on curved surfaces, heated with a constant heat flux, as well as the array of minijets. Numerical analyses, based on the mass, momentum and energy conservation laws, were conducted, regarding single phase and two-phase simulations. Focus was placed on the proper model construction, in which turbulence and boundary layer modeling was crucial. Calculations were done for various inlet parameters. Initial single minijet results served as the basis for the main calculations, which were conducted for two jet arrays, with flat and curved heated surfaces. Such complex geometries came from the cooling systems of electrical devices, and the geometry of cylindrical heat exchanger. The results, regarding Nusselt number, heated surface temperature, turbulence kinetic energy, production of entropy and vorticity, were presented and discussed. For assumed geometrical parameters similar results were obtained.
    Źródło:
    Archives of Thermodynamics; 2018, 39, 1; 147-166
    1231-0956
    2083-6023
    Pojawia się w:
    Archives of Thermodynamics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-9 z 9

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