Flow Analysis in Pipe of a Manifold Block

Hydraulic machines have many valves and piping parts. So there are problems that much space is needed and plumbing is more troublesome. Recently, as one of the methods to reduce the space and piping parts, manifold system is developed. This system is the method of connecting valves and actuators by using steel blocks that have pipelines inside. These blocks are called 'Manifold Block'.  Manifold block is generally classified into two types by way of machining. One is a solid manifold block (solid type) that has some holes by drilling. The other is a laminated manifold block (laminated type) that is composed of some blocks grooved and drilled in advance. In solid type, design of pipeline is relatively simple since its pipeline only connects some holes, but it is impossible to design pipeline freely. On the other hand, in laminated type, it is possible to design pipeline freely because it has pipes of rectangular groove, but it is difficult to weld blocks. So it takes much time to manufacture laminated type.  We deal with a solid manifold block and a laminated manifold block those are used for connecting hydraulic components. We investigate pressure drops of their pipe flow with computational fluid dynamics (CFD) and compare those of two types. The majority of all pressure drops in both types is pressure drop at corners. In solid type, pressure drop is affected by the distance between two corners and angle of corner against upstream corner. Solid type has round sectional area, but laminated type has a square one. So, pressure drop of laminated type is smaller than that of solid type. By experiment of visualization with an acrylic manifold block and comparison of pressure drop of CFD results with experimental results, the validity of CFD results is proved unless heavy cavitation occurs.