It is known that nano- and micromechanics require new approaches to right describing of surface-like phenomena which lead to an enhanced energy conversion. In this work, a general form of surface forces that consist of a contribution from both the friction and mobility components has been extended to collect the effects of bulk and surface motion of a fluid. Quite similar impact can be observed for a solid-fluid mixture, where the principle of effective stress for this new type of approach should be considered from the very beginning. The second motivation of our work is to present the multiscale domain of fluid-solid interaction which describes some “emergence effects” for materials with especially high volumetric surface densities.

The need of reformulation for basic concepts of fluid mechanics in order to account some enhancement phenomena in micro- and nano-flows is presented in the paper. The work is a general formulation of angular velocity slip condition which is developed from primary principles. It is postulated that the different slipping phenomena take place within a thin shell-like layer where a material particle undergoes independently: the slip velocity and angular slip velocity. We suppose also that the molecules rolling at the layer can give a serious contribution to the mass flow enhancement, and therefore, it can be a reason to inclusion of a mathematical modeling for molecules angular momentum. In this paper, we propose the general form of an angular momentum balance for the shell-like layer. This balance is expressed by the surface divergence of an unsymmetric surface stress and an unsymmetric surface couple stress, either by the bulk momentum and bulk moment of momentum or by a surface friction torque. With constitutive relations appropriate for a linear, viscous, isotropic fluid and the constitutive relation for frictional resistance, we obtain generalized Navier-type boundary equations for the slip velocity and the angular slip velocity. As special cases, Poisson’s type boundary condition and Aero–Bulygin–Kuvshlinskii’s angular slip condition are obtained. Proposed here boundary conditions have few applications in modeling of complex nano-flows phenomena. For instant, recently discovered electropumping phenomena by De Luca et al. (J Chem Phys 138:154712-1–154712-10, 2013a) are based on nano-coupling of angular momentum with linear momentum and the electroosmotic draining effect. The theoretical background relies upon different angular velocity slip of dipolar liquids when confined between hydrophobic and hydrophilic solid surfaces—this phenomenon combined with applied rotating electric field leads to pumping of liquid. In our opinion, a concept of angular velocity slip leads to an explanation of the electropumping effect enhancement in nano-channels.

Glass materials are constantly the base of life the majority of society. A lot of us, every morning brew a cup of tea or coffee in his favourite cup or look out glass pane in order to define the weather outside. Examples can be multiplied and multiplied. On account the role of glass materials, in most people life, has been decided to choice a glass material as a base to perform thermal FSI analysis. However the analysis would be nothing without calculative model. It is well known that there are various strength hypothesis, which treat of material strength dependency on reduced tension. In most cases, to the issue which is related to reduced tensions appointment which appear in analysed material, the Huber-Mises-Hencky hypothesis is used, but it is difficult to model glass material by this hypothesis. It happens because of specific properties of glass, which is amorphous body. And here, with help occurs the W.Burzynski, Huber’s student. Burzynski proposed the following reduced tension definition: ${\Phi }_f+\eta (p)\cdot {\Phi }_v=K$ , from which the Burzynski material effort is calculated:${\sigma }_B=\frac{1}{2k}\cdot \left[-(k-1)\cdot {\sigma }_m+\sqrt{{(k-1)}^2\cdot {\sigma }_m^2+4\cdot k\cdot {\sigma }_{HMH}^2}\right]$ . We reached to the idea, which is the introduction of material properties coefficient k. This parameter describes the relation of compressing strength to the tensile strength. Furthermore, R. Pecherski proposed the Burzynski hypothesis enlargement by Lode’s angle influence, which controls the participation of the energy density of distortion. Finally the Burzynski-Pecherski hypothesis is: ${\tilde{\eta }}_f(\theta ){\varphi }_f+{\tilde{\eta }}_v(p){\varphi }_v=K$ . Where θ describes Lode’s angle. In this work is presented the comparison of aforementioned hypothesis and delimitation the differences in received results stresses values by each one of hypothesis. As example of analysed problem the cold glass cup under nonstationary thermal load (which is simulated by boiled water) is taken under consideration. The analysis consist of flow calculations, bounded with filling the glass cup by hot fluid, import of geometry inner walls temperature values and finally calculation of reduced stresses using both strength hypothesis.

Reduction of greenhouse gases emissions is a key challenge for the power generation industry, requiring the implementation of new designs and methods of electricity generation. This article presents a design solution for a novel thermodynamic cycle with two new devices—namely, a wet combustion chamber and a spray-ejector condenser. In the proposed cycle, high temperature occurs in the combustion chamber because of fuel combustion by pure oxygen. As a consequence of the chemical reaction and open water cooling, a mixture of H₂O and CO₂ is produced. The resulting working medium expands in one turbine that combines the advantages of gas turbines (high turbine inlet temperatures) and steam turbines (full expansion to vacuum). Moreover, the main purpose of the spray-ejector condenser is the simultaneous condensation of water vapour and compression of CO₂ from condensing pressure to about 1 bar. The efficiency of the proposed cycle has been estimated at 37.78%. COM-GAS software has been used for computational flow mechanics simulations. The calculation considers the drop in efficiency due to air separation unit, carbon capture, and spray-ejector condenser processes. The advantage of the proposed cycle is its compactness that can be achieved by replacing the largest equipment in the steam unit. The authors make reference to a steam generator, a conventional steam condenser, and the steam-gas turbine. Instead of classical heat exchanger equipment, the authors propose non-standard devices, such as a wet combustion chamber and spray-ejector condenser.