• Energy Research

This article is devoted to the method of numerical modelling of aerodynamics when the air flows around fins of a special design, which is implemented in SolidWorks Flow Simulation. The study was carried out for three types of rib orientation, and the aerodynamic drag coefficients were determined for different values of the Reynolds number. It was confirmed that the drag coefficient values depend significantly on the flow regime. The lowest value of the drag coefficient is observed when the fins are oriented from a larger diameter to a smaller one. In the laminar regime (Re < 2300), the average value of CX = 1.04, in the transitional regime (2300 < Re < 10,000), CX = 0.74, and in the turbulent regime (Re > 10,000), CX = 0.22. Characteristic for this case of orientation is a significant decrease in the drag coefficient during the transition from laminar to turbulent regime; the minimum is observed at the flow speed in the range between 2 and 3 m/s.

This article presents the possibility of evaluating the efficiency of the heat exchange element with a special stamping plate, which is based on the results of computer simulation. The method is based on a comparative analysis of convective heat transfer models implemented in ANSYS using a k-ε turbulence model. To conduct the study, 3D models of three different types of cavity geometry formed between two heat exchange plates (flat plate, chevron plate, and plate with conical stampings) were built. Simulation was performed by finite element analysis in ANSYS for channels formed by the three types of plates, one of which is a new configuration. The results of hydrodynamic and heat exchange parameters allowed for establishing the efficiency of convective heat exchange for plates of known structures and to compare them with the proposed one. It was found that the plates with conical stamping form the smallest channels through which the fluid moves. The velocity of the coolant is uniform throughout the cross section of the channel and equal to 0.294 m/s; the value of the heat transfer coefficient is the largest of the three models and is 5339 W/(m K), while the pressure drop is 1060 Pa. Taking into account the simulation results, the best heat transfer parameters were shown by the channel formed by plates with conical stamping and the highest pressure drop. To increase the efficiency, indicated by the ratio of heat transfer coefficients to hydraulic resistance, the geometry of the plate with conical stamping was optimized. As a result of optimization, it was found that the optimal geometric parameters of the heat exchange plate with conical stamping were achieved at a 55° inclination angle and 1.5 mm height for the cone. The results of this study can be used in the design of heat exchange elements of new structures with optimal parameters for highly efficient heating of liquid coolants.

This paper reports the generalized results of computer simulation of physical processes at a rotor-disk film evaporating plant. Optimization of the operation mode cannot be achieved without establishing patterns in the course of physical processes. We have proposed a computer model of hydrodynamics that accounts for all the features, initial and boundary conditions. The results of computer simulations make it possible to adequately assess the effectiveness of using a rotor-disk film evaporating plant (RDFVP) for the concentration of heat-labile materials. We have established patterns in the course of physical processes within a structure of RDFVP by using computer simulation of hydrodynamics in the programming environment ANSYS and applying a k-e turbulence model. The result of simulation is the derived velocity fields of the concentrated fluid (w max =0.413 m/s) and the gas phase (w max =8.176 m/s), as well as the magnitude of values for shear stress τ=0.94·10 -6 Pa. It was established that the gas heat-carrier is characterized by the highly-turbulent flows with maximum values for kinetic energy TKE max =8.985·10 -1 m 2 /s 2 . The reliability of results is ensured by the correctness, completeness, and adequacy of physical assumptions when stating the problem and while solving it using the computer aided design system ANSYS. It has been established that the proposed structure is an effective alternative to equipment for the concentration of solutions. The data obtained could be used when designing heat-and-mass-exchange equipment for the highly efficient dehydration of thermolabile materials