Bernoulli force
Reaction force generated if a fluid flow changes direction and/or velocity. The force F acts on the fluid from the outside as a supporting force. The force exercised by the flow on the environment is the [...] the flow force The force F acts on the fluid from the outside as a supporting force (reaction force). The force exercised by the flow on the environment is the flow force This Bernoulli force can be seen
Viscosity
property of hydraulic fluids , which plays a role in its selection and the usage limits of several devices ( Figure V 27 ). In order to compare the viscosity of different fluids, they must relate to a [...] Property of a fluid to act against resistance to the opposite laminar movements of two neighbouring layers (DIN 1342 and IDN 51 550). A distinction is made between dynamic viscosity and kinematic viscosity
Flow coefficient αD
density of the pressure fluid p 1 - p 2 = pressure before the pressure resistance minus pressure after the flow resistance. The flow coefficient takes into account all losses due to fluid friction and turbulence [...] turbulence on flowing through the resistance. These losses appear in the energy balance as heating of the fluid. The flow coefficient is essentially dependent on the Reynolds number Re and the shape of the edge
Pressure
pascal: 1 Pa = 1 N/m2. In fluid technology p is mostly stated in bar (1 bar = 105 N/m2). However, MPa (106 N/m2) is also used. Pressure figures, if not otherwise stated, in fluid technology are to be understood [...] pressure as the reference variable. The pressure of a medium is one of the most important parameters in fluid technology. It occurs, as shown, in numerous variants that each have a specific significance for the
Materials for seals
Contact seals for fluid technology are predominantly manufactured from polymer materials in the group "elastic materials". The most important characteristics of these materials are their elasticity (adaptation [...] n to unevenness and to changing pressure), hardness (wear behaviour), resistance in the pressure fluid (swelling behaviour), sliding and friction behaviour, wear resistance among others. The elastic materials [...] thermoplastics for special tasks. Metal materials have become significantly less important for seals in fluid technology. Occasionally there are piston rings and sealing rings made of soft metals that must be
Acoustic impedance
element. The column of fluid has resistive behaviour, if the internal damping is ignored (acoustic impedance only has a real element). The acoustic impedance of a column of fluid in a pipe is dependent [...] achieved if the acoustic impedance of the pipe termination is the same as the impedance of the pipe (fluid + pipe walls). The acoustic impedance is used in hydraulics in particular for the design of pulsation
Volumetric losses
or velocity. Compression losses are caused by the compressibility of the hydraulic fluid. In the case of hydraulic fluids, the volumetric losses are described by the volumetric efficiency (cf. power losses [...] components by mating surfaces and rods. There are still leakage paths, through which the pressure fluid can flow. The external leaked oil flow Q Le for pumps and motors flows out of the pressurised chambers
Hydraulic cylinder
Cylinder designed to be used with hydraulic fluids at generally higher pressures (of around 100 bar and above). Given the relatively low compressibility of the fluid and the low weight of a piston, hydraulic [...] Hydraulic cylinder with piston : The mechanical force is generated by the action of the hydraulic fluid on a piston. With this approach, a single cylinder is able to apply forces ranging from just a few
Feedback
Hydraulic feedback : which uses a fluid signal, normally the pressure. Electric feedback : from electric signals, which are generally taken from a mechanical (fluid) variable using appropriate measuring [...] characteristic used to distinguish between feedbacks is the physical variable that is to be fed back. In fluid technology, this is primarily the location (path), force (pressure), velocity, acceleration, amongst
Redundancy
components are generally more vulnerable than fluid parts, the redundancy measures in fluid technology are focused on signal distribution . However, fluid systems may also have a redundant design. In doing