Flow simulations in rotary volumetric pumps and compressors with the fictitious domain method

The valve motion characteristics of a reciprocating pump

“…Mathematical models and finite element models [9][10][11][12][13] were established and then the motion of the valve disc was explored based on the U. Adolph motion differential equation [14,15]. Related experimental studies were mainly concerned about the fault diagnosis and signal processing of wearing parts of reciprocating pumps [16][17][18][19]. Pump parameters were generally acquired with pressure gauges and flow sensors installed on the pump suction or discharge pipe, and acceleration sensor mounted outside of the pump valve.…”

Adaptive Embedded/Immersed Unstructured Grid Techniques

“…Values that are too low do not allow the flow to adjust rapidly enough to the motion of the body, while values that are too high may produce artificial stiffness. Moreover, for body motions that are not completely divergence-free a large pressure buildup is observed (see [57] for a case of lobe-pumps). A major improvement was put forward by Mohd-Yusof [44], who proposed to evaluate first the usual right-hand side for the flow equations at immersed points (or cells), and then add a force such that the velocity at the next timestep would satisfy the kinematic boundary condition v = v b .…”

“…The advantage of the simple linear form given by (1) is that a point-implicit integration of the velocities is possible, i.e. the stiffness of the large coefficient c 0 can be removed with no discernable increase in operations [57]. The main problem with force fields given by (1), (2) is the choice of the constants c 0 .…”

“…They are based on either kinetic or kinematic boundary conditions near the surface or inside the bodies in the fluid. The first type applies an equivalent balancing force to the flowfield in order to achieve the kinematic boundary required at the embedded surface or within the embedded domain [2,4,14,18,20,26,28,43,44,47,49,[56][57][58]. The second approach is to apply kinematic boundary conditions at the nodes close to the embedded surface [1,17,30,39,40].…”

“…-'Dirty geometries' [1,9,11,30]; -Moving/sliding bodies with thin/vanishing gaps [9,57]; and -Physics that can be handled with isotropic grids (potential flow, Euler [1,9,17,27,30,31,48,50], Euler with Boundary Layer corrections [1], low Reynolds-number laminar flow and LES [2,4,14,20,22,23,28,43,55,58].…”