Jacek Wernik

Pneumatic pulsator design as an example of numerical simulations in engineering applications

The paper presents the part of the investigation that has been carried out in order to develop the pneumatic pulsator which is to be employed as an unblocking device at lose material silo outlets. The part of numerical simulation is reported. The fluid dynamics issues have been outlined which are present during supersonic airflow thought the head of the pulsator. These issues describe the pneumatic impact phenomenon onto the loose material bed present in the silo to which walls the pulsator is assembled. The investigation presented in the paper are industrial applicable and the result is the working prototype of the industrial pneumatic pulsator. The numerical simulation has led to change the piston shape which is moving inside the head of the pulsator, and therefore, to reduce the pressure losses during the airflow. A stress analysis of the pulsator controller body has been carried out while the numerical simulation investigation part of the whole project. The analysis has made possible the change of the controller body material from cast iron to aluminium alloy.

Three-Dimensional Flow Optimization of a Nozzle with a Continuous Adjoint

Abstract The article presents results of multi-criteria optimization of air nozzle topology. The optimization in the CFD has been recently developed since equations of flow in porous media were applied among others governing equations. Optimization is a seeking for extremum of an objective function with respect to the function constraints. With this definition in mind, the optimization by using a continuous adjoint for the current cases is a finding such channel topology which minimizes for example pressure or energy loss when the constraints of objective function are in the form of flow governing equations of momentum and continuity. This methodology of optimization makes a design process faster comparing to the methods related to Design of Experiments (DoE). However, for the sake of flow governing equations nonlinearity, the continuous adjoint method can be successfully applied only in relatively simply and steady-state cases. The reason is of possibility of finding the global extremum of the objective function only for that kind of cases. The results of optimization of two selected cases are presented in the article and show advantages and limitations of the method applied. The continuous adjoint simulation results indicate the nozzles design directions and can be applied in industry with limited reliability. The object of research reported in the article is the nozzle which is augmented equipment used with a pneumatic pulsator. The pulsators are devices that utilize an air stream to destruct vaults created in loose material structure. The pulsator productivity equipped with a nozzle depends on outlet pressure. Therefore, the optimization problem was stated so that pressure loss is to be as low as possible.

Air Evacuation from the Pressure Accumulator during Work Cycle of the Pneumatic Pulsator

Practically Applicable Vessel Evacuation is Presented in the Article. the Pressure Accumulatoris a Vessel which is a Part of the Pneumatic Pulsator which is Used for Unclogging Outlets of Silos. Apseudo-Schlieren Visualisation Method of Density Gradient and Values of Mach Number are Shown.There is Also a Time Variation of Outflow Velocity Analysed. Airflow Fluctuates after Time of 50 Ms.The Main Reason could Be the Inertia of the Air Mass and a Large Outlet Diameter Relative to the Mainvessel Dimensions

Applications of Process Integration Methodologies in Beet Sugar Plants

Abstract: This chapter discusses the applications of Process Integration methods to the design of energy systems, and water and wastewater systems, of beet sugar plants. Characteristic features of conventional sugar plants based on purification of raw beet juice and evaporating crystallisation are reviewed, the design of plant retrofit aimed at improvements in energy and water use is discussed, and case studies are presented. A concept of the sugar production process based on cooling crystallisation of raw beet juice is then outlined, and the design of an energy system and a water and wastewater system for a conceptual beet sugar plant employing the new process is discussed.

ICEEM07: Three-Dimensional Flow Optimization of a Pneumatic Pulsator Nozzle with a Continuous Adjoint

Abstract The article presents results of multi-criteria optimization of air nozzle topology. The optimization in the Computational Fluid Dynamics (CFD) has been recently developed since equations of flow in porous media were applied among others governing equations. Optimization is a seeking for extremum of an objective function with respect to the function constraints. With this definition in mind, the optimization by using a continuous adjoint for the current cases is a finding such channel topology which minimizes for example pressure or energy loss when the constraints of objective function are in the form of flow governing equations of momentum and continuity. This methodology of optimization makes a design process faster comparing to the methods related to Design of Experiments (DoE). However, for the sake of flow governing equations nonlinearity, the continuous adjoint method can be successfully applied only in relatively simply and steady-state cases. The method consists in seeking of a global extremum of objective function. This extremum can sometimes be find in only simple and stationary events. The results of optimization of two selected cases are presented in the article and show advantages and limitations of the method applied. The continuous adjoint simulation results indicate the nozzles design directions and can be applied in industry with limited reliability. The object of research reported in the article is the nozzle which is augmented equipment used with a pneumatic pulsator. The pulsators are devices that utilize an air stream to destruct vaults created in loose material structure. The pulsator productivity equipped with a nozzle depends on outlet pressure. Therefore, the optimization problem was stated so that pressure loss is to be as low as possible.

Numerical Simulations and Research of Heat Transfer in Pneumatic Pulsator

Abstract In loose material beds above silo outlets or in vertical channels immovable vaults can occur limiting or making impossible the downward movement of the loose material. To prevent vault creation or to destroy vault by aeration and separation of the loose material from encasing walls, a pneumatic pulsator can be applied. In order to optimize the head design, the flow phenomena were numerically simulated and the channels were preliminarily designed. The data obtained from simulation were also used as a basis for setting up an experimental stand to validate simulation results. During air flow in the channels due to frictional heat is produced, which is discharged from the pulsator to the environment. To increase the heat transfer in pneumatic pulsator, the external surfaces of channel are finned. Numerical simulations carried out conduction and convection heat transfer in the fins, and the results illustrated the temperature distribution on the surface of the body, the temperature distribution in the fins, stress distribution, value of factor of safety, the static displacement of the body and the distribution of air temperature along with the speed vectors. The results were compared with experimental and analytical results that confirm their correctness. The results confirm the rational design of the body in terms of thermal. The obtained temperature distribution using CFD agrees approximately with the values measured during the tests.

Study of Heat Transfer in Pneumatic Pulsator

The article presents selected results of research work aimed to rationalize and optimize the design of the pneumatic pulsator due to thermal conditions. Pneumatic pulsator is a device used in industry storing bulk and loose materials. It is attached to the silo, allowing their correct operation. The air friction against the inner wall of the pulsator causes the release of heat. In order to investigate the conditions of heat transfer, thermal calculations were made and then numerical simulations using Computational Fluid Dynamics (CFD) were conducted. Various fins options were examined. The objective was to maximize the heat flux discharged from the device. Temperature distribution on the surface of the fins designated by CFD corresponds to the distribution designated analytically. The results were confirmed by industrial tests. Numerical simulations mapping the heat exchange processes in a pneumatic pulsator have not yet been carried out.