Modelling airflow, heat transfer and moisture transport around a standing human body by computational fluid dynamics

Computational fluid dynamics analysis of drag and convective heat transfer of individual body segments for different cyclist positions

“…Such CHTCs are essential in these models to quantify the (convective) heat exchange of humans with the exterior environment. CHTCs for humans are usually determined by correlations with the wind speed from: (1) experiments on human manikins in a wind tunnel or a climatic chamber by means of calorimetry (Mitchell et al, 1969), surface heat flux measurements (de Dear et al, 1997;Ishigaki et al, 1993) or naphthalene sublimation (Nishi and Gagge, 1970) and (2) CFD simulations (Gao and Niu, 2004;Kilic and Sevilgen, 2008;Ono et al, 2008;Sorensen and Voigt, 2003). There is still room for improvement regarding these CHTC-wind speed correlations for cyclist applications: (1) The CHTC magnitude and distribution over the body surface are strongly dependent on the flow field around the cyclist, which is determined by the cyclist position and anthropometric characteristics.…”

Numerical Investigation of the Effect of Variable Baffle Spacing on the Thermal Performance of a Shell and Tube Heat Exchanger

“…These pressure drop regions are shown in Figure 1 for shell and tube heat exchangers in general: The Bell-Delaware method is more complicated than the Kern method because of some additional parameters that are involved in the calculations. These parameters concern various leakages and bypass streams on the shell side and their effect on the shell side ideal heat transfer coefficient is described by Equation (18): The ideal heat transfer coefficient (hid) described in the Bell-Delaware method for pure crossflow in an ideal tube bank and is calculated from Equation (19), where Ji is Colburn j-factor and it can be found as a function of the shell side Reynolds number, As is the cross-flow area at the centerline of the shell for one cross-flow between two baffles. Jc is the correction factor for baffle cut and spacing, Jl is the correlation factor for baffle leakage effects including tube-to-baffle and shell-to-baffle leakage, Jb is the correction factor for bundle bypassing effects and Js is the correction factor for variable baffle spacing at the inlet and outlet.…”

“…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: …”

“…The number of total elements was about 6.0 million and the mesh should be well designed to resolve the important flow features which are dependent upon flow condition parameters. In numerical calculations, mesh generation is very crucial for getting accurate predicted results and reducing the computation time [9,12,14,18,19]. The mesh structure of the surfaces of the computational domain and the section view of this domain are shown in Figure 6.…”

The effects of using different type of inlet vents on the thermal characteristics of the automobile cabin and the human body during cooling period

“…This turbulence model is generally used for such Fig. 2 The slide of volume cells at Z=−0.28 m calculations due to stability and precision of numerical results in literature [6][7][8]. The RNG-based k-ε turbulence model is derived from the instantaneous Navier-Stokes equations, using a mathematical technique called RNG methods.…”