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This paper deals with a numerical simulation of the thermal and fluid‐dynamic behaviour of double‐pipe condensers and evaporators. The governing equations of the fluid flow (continuity, momentum and energy) in both the tube (evaporating or condensing flow) and the annulus (single‐phase flow), together with the energy equation in the tube wall, are solved iteratively in a segregated manner using a one‐dimensional, transient formulation, based on an implicit step by step numerical scheme in the zones with fluid flow (tube and annulus), and an implicit central difference numerical scheme in the tube wall, solved by means of the Tri‐Diagonal Matrix Algorithm (TDMA). This formulation requires the use of empirical information for the evaluation of convective heat transfer, shear stress and void fraction. Two criteria to calculate the location of the points of transition between single‐phase and two‐phase flow are tested. An analysis of the different parameters used in the discretization is made. Some illustrative results corresponding to the solution of a condenser and an evaporator using two different working fluids (R–12 and R–134a) are presented.

In this paper a numerical simulation, based on finite difference techniques, has been developed in order to analyse turbulent natural and mixed convection of air in internal flows. The study has been restricted to two‐dimensional cavities with the possibility of inlet and outlet ports, and with internal heat sources. Turbulence is modelled by means of two‐equation k‐ε turbulence models, both in the simplest form using wall functions and in the more general form of low‐Reynolds‐number k‐ε models. The couple time average governing equations (continuity, momentum, energy, and turbulence quantities) are solved in a segregated manner using the SIMPLEX method. An implicit control volume formulation of the differential equations has been employed. Some illustrative numerical results are presented to study the influence of geometry and boundary conditions in cavities. A comparison of different k‐ε turbulence models has also been presented.

The purpose of this paper is to present transient turbulent natural convection with surface thermal radiation in a square differentially heated enclosure using non-primitive variables like stream function and vorticity.

The governing equations formulated in dimensionless variables “stream function, vorticity and temperature,” within the Boussinesq approach taking into account the standard two equation k-ε turbulence model with physical boundary conditions have been solved using an iterative implicit finite-difference method.

It has been found that using of the presented algebraic transformation of the mesh allows to effectively conduct numerical analysis of turbulent natural convection with thermal surface radiation. It has been shown that the average convective Nusselt number increases with the Rayleigh number and decreases with the surface emissivity, while the average radiative Nusselt number is an increasing function of these key parameters. It has been shown that a presence of surface thermal radiation effect leads to an expansion of the eddy viscosity zones close to the walls.

It should be noted that for the first time in this paper we used stream function and vorticity variables with very effective algebraic transformation of the mesh in order to create a non-uniform mesh for an analysis of turbulent flow. Such method allows to reduce the computational time essentially in comparison with using of the primitive variables. The considered method has been successfully validated on the basis of the experimental and numerical data of other authors in case of turbulent natural convection without thermal radiation. The used numerical method would benefit scientists and engineers to become familiar with the analysis of turbulent convective heat and mass transfer, and the way to predict the properties of the turbulent flow in advanced nuclear systems, in industrial sectors including transportation, power generation, chemical sectors, ventilation, air-conditioning, etc.

The purpose of this study is to investigate the flow interaction between the cavities and its impact on heat transfer. The role of the openings is examined and three strategies are considered: one opening, two openings on single side and two openings on double sides.

A two-dimensional laminar natural convection heat transfer in multilayered open cavities was numerically investigated. The governing equations in primitive variables were discretized by the finite volume method and solved by SIMPLE algorithm.

The results show that for the cavities with one opening, the flow in the cavities is connected with each other. The exhaust hot fluid from the lower cavity was entrained into the upper cavities by thermal buoyancy and hence the heat transfer in the upper cavities was decreased because of thermal accumulation. Two openings on the single side could strengthen the flow interaction between the cavities and then enhance the heat transfer. However, the double-sided openings eliminated the flow interaction between the cavities and thus the fluid flow and heat transfer characteristics in all cavities are independent. It was concluded that the flow interaction between the multilayered open cavities has an importance effect on the heat transfer in the cavities.

The flow interaction between the multilayered open cavities was illustrated. The effect of flow interaction on the heat transfer in the cavities was investigated. The role of openings in the flow interaction and heat transfer in cavities was explored. The cavity below affects above cavity for the openings on single side. No interaction exists between the cavities with openings on double sides.

Purpose: Social rejection is a negative interpersonal experience that leads to emotional, cognitive, and physiological outcomes. We develop a theoretical model arguing that social rejection in workplace settings can alter employees' personal values in either the short- or the long term. Methodology: This is a theoretical essay based on three theories: (1) human values; (2) affective events; and (3) shattered assumptions. Findings: In the proposed model, an employee's emotional reactions to social rejection in the workplace (emotional distress or emotional numbness) partially mediate the relationship between the experience of social rejection and short- or long-term development of self-protective (rather than self-expansive) personal values. Originality: The processes whereby social rejection at work leads to personal value change remain largely unexplored to date. The proposed model represents an initial attempt to understand this process, including the effects of emotional distress (long term) and emotional numbness (short term). Research Implications: The model introduces the mechanisms whereby social rejection in the workplace leads to short-term and long-term changes in individual values and has potential to serve as a launchpad for future research interest in this phenomenon. Practical Implications: The framework proposed in this chapter should help scholars to understand better the dynamics of social rejection in the workplace and how this phenomenon affects employees' values in work settings, both in the short- and long term.

Due to the recovery of the quality of life coming from a real estate boom and due to the extensive possibilities for leisure and work, the young generation in Spain looks with more optimism into the future as did generations before. Still, Spain is a nation with low employment prospects. This puts many professionals in a difficult position, having to sacrifice family relations for a better job. Another problem is the rate of university degrees, which is over the European average. Therefore, Generation Z has higher goals for their lives than previous generations. One of the traditional problems is that young people get high marks in their professional degrees but have a lack of employability skills and are therefore not always success in their first apprenticeship contract with companies. Generation Z has social skill problems with respect to empathy, communication and conflict management. Due to their digital style of life, they have substituted the gregarious relationships leisure for the bedroom culture of social networks.

This study aims to present the development and validation of a scale to measure the attitudes of Latin American business students toward sustainable management practices in the economic, social and environmental dimensions.

Using a nonprobabilistic sample, the appreciation for sustainable practices in students (ASP-S) scale was administered to a total of 653 undergraduate and graduate business students in Argentina, Colombia, Mexico and Peru. A range of psychometric validity (construct, convergent and discriminant) and reliability criteria were applied.

Construct, convergent and discriminant validity was obtained from the ASP-S scale across all samples. During the internal validation process, two factors were found: systemic consciousness (ten items) and sustainable business leadership (nine items), both of which obtained acceptable reliability indices. The resulting structure is equivalent in all four countries.

The instrument can be applied by educators and learning assurance areas to diagnose and measure the effectiveness of pedagogical strategies used in sustainability courses taught at Latin American business schools. As a result, it has applications for curriculum design. As a valid and reliable instrument set in the context of regional business praxis, it can promote an understanding of sustainable behaviors and practices in future Latin American leaders.