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• Application of the Euler-Euler method to CFD modelling of the flow of ice slurry. • Low slip velocity of solid particles. • Highest slip velocities are observed near the channel sidewalls. • Homogeneous flow, lower border velocities for downward compared to upward flow. • Flow map of ice slurry for vertical flow in slit channel. In this article, the Euler-Euler method was applied to CFD modelling of adiabatic ice slurry flow, for different flow directions in a vertical slit channel. The mean relative accuracy of determining pressure drops compared to experimental studies was 5.6%. Calculations showed that the relative slip velocity and the effect of flow direction on slip velocity increase with decreasing carrier fluid concentration, decreasing mean flow velocity, and decreasing mean solid particles volume fraction. The mean particle slip velocity does not exceed 4%, and local slip velocity values can be 58% of the mean suspended solids flow velocity. For heterogeneous flow, the highest slip velocities occur at a distance of 15% of the channel width from the channel sidewalls. The shape of the solid particles distribution profile is determined by the mean flow velocity and the mean solid particles volume fraction. Excluding the area at a distance of 8% of the channel width from the sidewall where local maximum (for low velocities) and minimum (for higher velocities) values may occur, the profile is stabilised in the central part of the channel. In this study, the boundary curves between heterogeneous and homogeneous flow were determined for ice slurry flow in a vertical slit channel. [ABSTRACT FROM AUTHOR]

• Flow resistances of ethanol ice slurry in a vertical slotted channel. • Determination of dynamic plastic viscosity and shear stress of ethanol ice slurry. • Impact of flow direction, settling velocity on flow resistance. • Dimensionless relationships for the determination of Fanning friction factors. • Generalized non-Newtonian fluid flow through a vertical slit channel. The paper presents the results of experimental flow investigations of an ethanol-based ice slurry flowing up and down a vertical slit channel. The impact of flow direction, carrier fluid concentration, ice mass fraction and mean velocity on pressure drop values has been investigated. Stronger mutual interaction between the phases on flow resistances was observed for low carrier fluid concentrations and in the laminar range of ice slurry flow. The measured resistance values for downward flow in the laminar area were 6–10% higher than the pressure drops for upward flow, while in the turbulent flow area they were 1–8% higher. Using the generalized non-Newtonian fluid model, the authors have proposed equations for calculating the friction factors for a vertical slit channel and various flow directions. [ABSTRACT FROM AUTHOR]

• New correlations for Nu number of ethanol ice slurry in a vertical slit channel. • The effect of flow direction on the values of α coefficients was investigated. • For laminar flow, the melting process has a greater effect of on α coefficient. • For turbulent flow, the convection process has a greater effect on α coefficient. • The upward flow, high ice mass fraction increase the αcoefficients. The article concerns the heat transfer process of ethanol ice slurry during downward and upward flow in a vertical slit channel (3x35.8x700 mm) under constant heat flux density conditions. Experimental studies were conducted for three initial concentrations of ethanol (X vai = 10.5 %, 13.2 %, 15.8 %) and mass fractions of ice of 0 ≤ x s ≤ 30 %. For upward flow, heat transfer coefficients were 6–14 % higher than for downward flow. For laminar flow, a greater effect of the melting process was observed, and for turbulent flow, the convection process had a greater effect on heat transfer coefficients. For laminar flow, the heat transfer coefficients of the ice slurry can be 200 % higher than the corresponding values for the carrier fluid. In turbulent flow, the corresponding increase in heat transfer coefficients did not exceed 15 %. For generalised non-Newtonian flow of ice slurry, criterion relationships were proposed for calculating heat transfer coefficients, taking into account the effect of the concentration of the carrier fluid, mass fractions of ice, its melting process, as well as the nature and direction of the flow. [ABSTRACT FROM AUTHOR]

The paper presents the phenomena accompanying the processes of non-adiabatic transport of ice slurry with ice mass fraction values below 20% in the transport sections of the system, assuming the conditions of significant changes in hydrostatic pressure. The subject of the analysis presented herein was to indicate the influence of hydrostatic pressure values on melting and secondary recrystallisation phenomena in the case of medium expansion in a vertical shaft pipeline and a three-chamber PES distributor. The paper proposes a computational model to determine the mass fraction of ice in the downstream section of the supply system: upstream and downstream of the PES distributor. The presented calculation results indicate that a reduction in the mass fraction of ice in the range of 0.004% per 1 m of the pipeline could be observed in vertical shaft pipelines. Maximising the enthalpy flux of the slurry at the inlet to the secondary circuit and minimising the temperature of the return water to the chiller favours mixing rates in the PES three-chamber distributor below 7%, which increase as the mass fraction of ice decreases. • Ice slurry applications in central air-conditioning systems of mining plants. • Ice slurry flow and heat transfer in shaft pipelines and PES distributors. • Ice slurry melting and recrystallisation in primary and secondary circuits. [ABSTRACT FROM AUTHOR]

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The paper presents the results of experimental research of pressure drop and heat transfer coefficients of ice slurry during its flow through tubes of rectangular and slit cross-sections. Moreover, the work discusses the influence of solid particles, type of motion and cross-section on the changes in the pressure drop and heat transfer coefficient. The analysis presented in the paper allows for identification of the criterial relations used to calculate the Fanning factor and the Nusselt number for laminar and turbulent flow, taking into account elements such as phase change, which accompanies the heat transfer process. Ice slurry flow is treated as a generalized flow of a non-Newtonian fluid. [ABSTRACT FROM AUTHOR]

Abstract: The paper presents the results of experimental research on heat transfer of ice slurry during its flow through tubes of circular, rectangular and slit cross-sections. Moreover, the work discusses the influence of solid particles, type of motion and cross-section on the changes in the heat transfer coefficient. The analysis presented in the paper allows for an identification of the criterial relations used to calculate the Nusselt number for laminar and turbulent flow, taking into account elements such as phase change, which accompanies the heat transfer process. Ice slurry flow is treated as a generalized flow of a non-Newtonian fluid. [Copyright &y& Elsevier]

Abstract: In this paper, we present results of the studies of pressure drops during laminar and turbulent flows of ice slurry produced on the basis of 10.6% ethanol solution. The results, obtained at various ice mass fractions, include pressure drops determined in horizontal ducts of circular, rectangular, and slit cross-sections. The critical Reynolds numbers were also determined. By introducing the Kozicki''s generalized definition of the Reynolds number, it was possible to verify the Fanning, Blasius and Dodge–Metzner–Kozicki relations used for determining ice slurry pressure drops during its flow through channels of various cross-sections. [Copyright &y& Elsevier]

Abstract: In this paper we present results of the studies of ice slurry flow in horizontal tubes. The possibility of treating the rheological parameters of ice slurry as being those of Bingham fluid was confirmed. The values of parameters (mass fraction, flow velocity) corresponding to the laminar, intermediate and turbulent flow were determined which permits to optimize the flow in the systems working with this cooling agent. Critical flow velocity and mass fraction of ice values were determined thereby; they correspond to a change in character of an ice slurry flow from a laminar to turbulent motion. Experimental results were compared to the analytical results, based on the Hedström and Tomita algorithms (the laminar and turbulent flow, respectively). The comparison showed a very good agreement between these data. [Copyright &y& Elsevier]

Abstract: In this paper, we analyzed the possibility of the simulations of ice slurry flow based on the known CFD procedures, for both Bingham fluids and mulitiphase flow models (the mixture and Eulerian models). It was shown that in the laminar region, the models selected (the Bingham and mixture model) gave a correct description of momentum transfer. In the turbulent range, corresponding to low values of the Reynolds number, the best agreement between experimental and simulation results (for the single-phase as well as for the multiphase Eulerian model) was obtained when the RNG k–ε turbulence model with the enhanced wall treatment algorithm was selected. [Copyright &y& Elsevier]

Abstract: This paper presents results of studies on heat transfer in ice slurry flows through horizontal tubes. On the basis of the energy equation and experimental results, the authors developed their own dimensionless relationships to determine local values of heat transfer coefficients for turbulent and laminar flows. Appropriate parameters were introduced to these expressions, in order to account for the effects of the following: the rheological properties of ice slurry, phase change, and the multiphase flow character. The second part of this paper discusses the possibility of modeling heat transfer in ice slurry tube flows using the CFD (fluent) methods. Correct description of heat transfer in ice slurry flows in tubes was made possible by assuming a single-phase model for Bingham fluid, and the enthalpy-porosity method for the analysis of melting, as well as by taking into account variations of the heat conductivity in a moving suspension. [Copyright &y& Elsevier]

This paper looks at entropy generation during ice slurry flow in straight pipes and typical heat exchanger structures used in refrigeration and air-conditioning technology. A dimensionless relationship was proposed to determine the interdependency between flow velocity and the volume fraction of ice, for which the entropy generation rates were at the minimum level in the case of non-adiabatic ice slurry flow. For pipe flow, the correlation between the minimum entropy generation rate and the overall enhancement efficiency was analyzed. As regards heat exchange processes in heat exchangers, the authors analyzed the relationship between the minimum entropy generation rate and the heat exchange surface area and exchanger efficiency. [ABSTRACT FROM AUTHOR]