Maksim A. Pakhomov

Numerical Simulation of Flow Structure and Heat Transfer in a Swirling Gas-Droplet Turbulent Flow Through a Pipe Expansion

The effect of droplets evaporation on the flow structure, turbulence modulation and heat transfer enhancement in a swirling two-phase flow in a pipe with sudden expansion is numerically investigated. The numerical model is based on the Eulerian approach. The gas phase is treated as a continuum while the droplets are considered as the dispersed phase. The set of steady-state 3D RANS equations is used for the computations of the gas phase. In the study the second moment closure (SMC) is used for the gas phase. Two-way coupling is used along with the particulate feedback onto the mean distribution of the gas phase. Intensification of the heat transfer by increasing the swirl parameter (the maximum increase in heat transfer is up to \(50\,\%\)) is shown. The position of the maximum heat transfer shifts upstream. The predicted results are in good agreement with the measurement data for the confined two-phase swirling flow with solid particles.

Numerical Modeling of Flow and Heat Transfer in a Turbulent Gas-Droplets Boundary Layer

Wall-bounded turbulent gas-droplets flows with phase changes employ very often in a vide range of industrial processes. The addition of the particulate phase to the already complicated turbulent flow substantially increased the description of the problem.

Comparison with Experimental Data in a Flat Plate Turbulent Gas-Particles Boundary Layer

Unlike for laminar boundary layer, we failed to come across in the literature measured data concerning the flow structure and heat transfer in turbulent mist gas-droplets flows over the flat vertical plate. That is why in the present section is given a comparison of our calculated data with available well-known experimental data on the structure of turbulent boundary layer air flows laden with solid particles (Rogers and Eaton 1990, 1991).

Laminar Mist Flows Over a Flat Plate with Evaporation

The experimental and numerical study of laminar two-phase boundary layer with evaporating liquid droplets performed in relatively small number of works (Bhatti and Savery 1975; Heyt and Larsen 1970; Hishida et al. 1980, 1982; Osiptsov and Shapiro 1989, 1993; Osiptsov and Korotkov 1998; Pakhomov and Terekhov 2012; Terekhov and Pakhomov 2002; Terekhov et al. 2000; Trela 1981). Nevertheless investigation of such flows is a topical problem for various short channels that are widely used in different heat transfer equipment.

Flow Dynamics, Heat and Mass Transfer in Two-Phase Laminar and Turbulent Boundary Layer on a Flat Plate with and without Heat Transfer Between Solid Wall and Flow: The State-of-the-Art

In the section the results of experimental and numerical studies of disperse particles behavior and their influence on the parameters of gas flow in the laminar and turbulent boundary layers are given and analyzed. Extensive experimental and theoretical information on the dynamics and heat and mass transfer in the two-phase laminar and turbulent systems is given in the reviews (Brennen 2006; Clift et al. 1978; Crowe et al. 1998; Drew 1983; Friedlander 1977; Ishii 1975; Loth 2006; Michaelides 2006; Nigmatulin 1991; Osiptsov 1997; Soo 1967; Varaksin 2007; Zaichik et al. 2008). Note that from the analysis of the now available experimental and numerical results it is obvious that influence of the particles on the near-wall flow may be of two kinds. First, the dispersed phase may effects the flow in the boundary layer for the account of its modification. Second, th e particles directly influence the flow in the boundary layer due to their inertial nature, namely for the account of the present dynamic and heat interface slip.

Flow and Heat and Mass Transfer in a Laminar Gas-Droplets Boundary Layer

In the chapter is considered the steady flow of the gas-droplets flow in the laminar and turbulent boundary layer taking into account evaporation of monodispersed droplets, interfacial interaction, particles deposition on the plate surface, heat transfer deposited particles with the wall and vapor diffusion in the gas–vapor mixture.

Numerical Study of Flow and Heat Transfer in Confined and Unconfined Round Mist Impinging Jet

The work presents results of numerical investigation of flow structure and heat transfer of unconfined and confined impact mist jets with low mass fraction of droplets (ML1 ≤1%). The downward gas-droplets jet is issued from a pipe and strikes into the center of the circular target wall. Mathematical model is based on the solution to RANS equations for the two-phase flow in Euler approximation. For the calculation of the fluctuation characteristics of the dispersed phase model equations of Derevich and Zaichik [1] and Zaichik et al. [2] were applied. Predictions were performed for the distances between the nozzle and the target plate x/(2R) = 0.5–10 and the initial droplets size (d1 = 5–100 μm) at the fixed Reynolds number based on the nozzle diameter, Re = 26600. Addition of droplets causes significant increase of heat transfer intensity in the vicinity of the jet stagnation point compared with the one-phase air impact jet.Copyright