“…5, 6 and 7, respectively. As shown in these figures, the obtained values have a high agreement with the experimental data [16]. The maximum difference between the experimental and numerical velocity, temperature and relative humidity is 0.03 m/s, 0.4 °C and 0.5 %, respectively.Fig.…”
Section: Introductionsupporting
confidence: 71%
“…For the validation of the present model, the calculated result was compared to the available experimental data in the literature [16]. The compression for the velocity, temperature and relative humidity are shown in Figs.…”
The aim of this study is to determine optimum hybrid heating systems parameters, such as temperature, surface area of a radiant heater and vent area to have thermal comfort conditions. DOE, Factorial design method is used to determine the optimum values for input parameters. A 3D model of a virtual standing thermal manikin with real dimensions is considered in this study. Continuity, momentum, energy, species equations for turbulent flow and physiological equation for thermal comfort are numerically solved to study heat, moisture and flow field. K − ɛRNG Model is used for turbulence modeling and DO method is used for radiation effects. Numerical results have a good agreement with the experimental data reported in the literature. The effect of various combinations of inlet parameters on thermal comfort is considered. According to Pareto graph, some of these combinations that have significant effect on the thermal comfort require no more energy can be used as useful tools. A better symmetrical velocity distribution around the manikin is also presented in the hybrid system.
“…5, 6 and 7, respectively. As shown in these figures, the obtained values have a high agreement with the experimental data [16]. The maximum difference between the experimental and numerical velocity, temperature and relative humidity is 0.03 m/s, 0.4 °C and 0.5 %, respectively.Fig.…”
Section: Introductionsupporting
confidence: 71%
“…For the validation of the present model, the calculated result was compared to the available experimental data in the literature [16]. The compression for the velocity, temperature and relative humidity are shown in Figs.…”
The aim of this study is to determine optimum hybrid heating systems parameters, such as temperature, surface area of a radiant heater and vent area to have thermal comfort conditions. DOE, Factorial design method is used to determine the optimum values for input parameters. A 3D model of a virtual standing thermal manikin with real dimensions is considered in this study. Continuity, momentum, energy, species equations for turbulent flow and physiological equation for thermal comfort are numerically solved to study heat, moisture and flow field. K − ɛRNG Model is used for turbulence modeling and DO method is used for radiation effects. Numerical results have a good agreement with the experimental data reported in the literature. The effect of various combinations of inlet parameters on thermal comfort is considered. According to Pareto graph, some of these combinations that have significant effect on the thermal comfort require no more energy can be used as useful tools. A better symmetrical velocity distribution around the manikin is also presented in the hybrid system.
“…In this software flow and temperature fields were computed by a three dimensional CFD method. This software solves continuum, energy and transport equations numerically and the coupled algorithm was chosen for pressure-velocity coupling, the k-ε realizable model was used for turbulence modeling and this model was used for such calculations due to stability and precision of the numerical results in the available literature [6,12,[18][19][20][21][22]. The governing equations for steady state conditions are shown below: …”
Section: Cad Model Of the Heat Exchangermentioning
Abstract:In this present study, numerical and theoretical analysis were both used to investigate the effect of the variable baffle spacing on the thermal characteristics of a small shell and tube heat exchanger. The numerical study was performed by using a three dimensional computational fluid dynamics (CFD) method and the computations were performed under steady-state conditions. We employed five different cases where the first had equal baffle spacing and the others had variable ones considering different configurations for balancing the pressure drop on the shell side. Theoretical calculations were run using the Bell-Delaware and Kern methods which are the most commonly used methods in the available literature. We show that the thermal performance of a shell and tube heat exchanger can be improved by evaluating together the results of the CFD and Bell-Delaware methods. From the numerical results, we can say that variable spacing with centered baffle spacing scheme can be proposed as an alternative shell side construction layout compared to an equal baffle spacing scheme. The numerical results were in good agreement with the theoretical data in the available literature.
“…However, a large number of these items mainly studied the influence of ventilation or air conditioning system in forced convection and often without taking into account the radiation [6][7][8]. Sevilgen et al [9] conducted a study in natural convection taking into account the radiation with a simplified model of heater. Moreover, Sharma et al [10] and Borjini et al [11] showed that the radiation has an important role and can change behavior of the thermo-aeraulic field in natural convection flow.…”
a b s t r a c tThis note addresses an industrial application concerning the way to optimize the surface temperature of commercial electrical heater. The aim of this paper is to reduce the temperature on accessible surfaces and electrical heater in order to respect the European standards and quality criteria imposed by the manufacturer. This target must be achieved by changing only the emissivity distribution of the electric heater components. A numerical study of the natural convection flow coupled with radiation is carried out in a heated room with an electric heater. The physical model includes the transport equations of mass, momentum, energy and radiative transfer which are solved numerically. Thermo-physical properties of the fluid are assumed to be dependent of the temperature. The numerical simulations are carried out for a two-dimensional, steady and turbulent flow using the finite volume approach. Results showed the influence of emissivity distribution of the electric heater components. The reducing of the heating foil emissivity allowed to decrease the radiative contribution on the foil and its temperature.
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