CFD-strømningsanalyse og optimalisering av et rørsystem i en gjødselspreder | CFD flow analysis and optimization of a manure spreader pipe system

English. The agriculture is like the rest of the society constantly evolving. Together with strict environmental requirements, the agriculture is met with an increasing demand for productivity. Agromiljø AS provides land application systems for livestock manure. They are specialized in the manufacture of equipment known as the “stripespreder”, hereafter addressed as the band spreader. The band spreader applies the manure from multiple sources, to the soil surface in uniformly separated bands. Agromiljø would like to optimize their system, so that the band spreader can handle a higher amount of manure, and thus a reduction in energy consumption. It is this desire to analyze and optimize the band spreader process that poses as the background this thesis. In the approach to optimize the band spreader system, the flow pattern and pressure loss in a specific part of the band spreader system was analyzed. In order to achieve this, Finite Element Method (FEM) in SolidWorks was utilized. By using this method, specific points contributing to pressure loss in the system was identified. In addition to FEM, calculations were performed by hand to assess whether or not the simulation results were realistic. The calculations showed a higher pressure loss compared to the results obtained in the FEM simulation. However, the simulation results were considered valuable and were thus been implemented in the optimization process. In both the FEM simulation and in the calculations, rheological parameters obtained by Y. R. Chen (in 1986) in a viscosity study of 4,5 % dry matter beef cattle manure were used. It was the section between the inlet of the band spreader and the manifold located on the top of the spreader that was analyzed in this work. The main function of this part is to lead the manure from the flat hose up to the distributer house. This section also comprises of two valves that enables to empty the hose without going through the distributer house and to close it and build up pressure. A T-bend redirect the flow 90° upwards. A turn coupling allows the hose to rotate in the horizontal plane, which makes it flexible and prevents drag in the hose. A manometer are placed inside the turn coupling, which makes it possible to measure the static pressure before opening. The system also contains two separate decoupling points, one Bauer coupling and an AM-coupling.The simulation performed in SolidWorks showed that there are three specific points in the system where strong turbulence arises: At the deflection of the T-bend, at the pressure transmitter, and in the Bauer coupling. After the T-bend, the turbulence is maintained throughout the system.By using the information gained in the analysis, a new optimized 3D system was designed and tested in SolidWorks. Tin this new system the pressure loss was reduced by 86% compared to the original. In addition, less turbulence was recorded throughout the system. In the optimized system, the inner diameter of the pipes was increased. This increase in dimensions caused 72% of the reduction in pressure loss. The remaining 28% is a result of changes in the system set up. The most important change in set up is the introduction of a three-way ball valve. This valve replaces gatevalve, a two-way ball valve and a T-bend. In this way, there is a reduction in number of system components resulting in a better flow, lower pressure loss, and therefore also lower production and operation costs.It is important to emphasize that this work is only a theoretical analysis. Therefore, the new system should be thoroughly tested before implementing it into real life production.

English. Agromiljø AS provides land application systems for livestock manure.

Agromiljø AS

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