Excavator multi-way valve rotary coupling spool moves 5mm to the right of the model boundary condition setting: the new and old valve inlet speed are both
Is set to 2.77m / s, 2.944m / s, the outlet pressure is 0MPa, that is, the rotary motor is unloaded, its turbulence intensity is taken at 10%, and the inlet and outlet hydraulic diameters are 0.012m and 0.0085m, respectively. (1) Static pressure distribution Figure 4-14 shows the static pressure cloud diagram of the axial section of the original excavator multi-way valve rotary coupling spool shifted 5mm to the right (unit: MPa; hereinafter referred to as the original right shifted 5mm return static pressure Cloud image). It can be known from the diagram a) that the inlet pressure reaches 14 MPa. After passing through the variable U-shaped throttling groove, the total pressure loss is 14 MPa. From the diagram b), it can be seen that the pressure loss after the return U-shaped throttling groove is 14 MPa. There is no vortex field in the throttle groove and no negative pressure is formed. From b), it is known that the pressure loss is mainly at the position where the oil has just entered the orifice. The pressure gradient at the inlet is large, and the pressure gradient at the outlet is small.
Figure 4-15 shows the static pressure cloud diagram (unit: MPa; hereinafter referred to as the new right-shift 5mm return oil pressure cloud diagram) of the new excavator multi-way valve rotary coupling spool to the right of 5mm. It can be known from the diagram a) that the inlet pressure reaches 9.5 MPa, and the pressure loss is 9.5 MPa after passing through the variable U-shaped throttle groove; from the diagram b), it can be known that the pressure loss is 9.5 MPa after the pressure oil passes through the return U-shaped throttle groove MPa. There is no vortex field in the throttle groove, and negative pressure is locally formed.
From b), it is known that the pressure loss is mainly at the position where the oil has just entered the orifice. The pressure gradient at the inlet is large, and the pressure gradient at the outlet is small.
(2) Speed distribution Figure 4-16 shows the velocity cloud diagram of the original excavator multi-way valve rotary coupling spool to the right by 5mm return oil axial section (unit: m / s; hereinafter referred to as the original right shift 5mm return oil velocity cloud map ). It can be known from the diagram a) that the inlet velocity is 10m / s. When the oil passes through the minimum point of the variable U-shaped throttle groove, the velocity can reach 160m / s; from the diagram b), it can be clearly known that the pressure oil passes through the inlet U shape After the throttle groove, the speed rapidly increased from 10m / s to 160m / s, resulting in a local temperature rise.
From b), it is known that the velocity is mainly generated at the minimum flow area of the throttle groove, which is also consistent with the flow continuity equation, indicating the correctness of the flow field analysis. The local high speed leads to a local temperature rise of the oil, which oxidizes the oil and produces local expansion and deformation of the valve body, resulting in stuck valves. Figure 4-17 shows the velocity cloud diagram of the axial cross section of the new excavator's multi-way valve rotary joint spool moving 5mm to the right (unit: m / s; hereinafter referred to as the new right shift 5mm oil return velocity cloud). It can be known from the diagram a) that the inlet velocity is 10m / s. When the oil passes through the minimum point of the variable U-shaped throttle groove, the velocity can reach 120m / s; from the diagram b) it can be clearly
Knows that after the pressure oil passes through the oil-introducing U-shaped throttle groove, the speed rises rapidly from 10m / s to 120m / s, resulting in a local temperature rise.
From b), it is known that the velocity is mainly generated at the minimum flow area of the throttle groove, which is also consistent with the flow continuity equation, indicating the correctness of the flow field analysis. The local high speed causes the local temperature rise of the oil, which oxidizes the oil and produces local valve body deformation, resulting in stuck valves.
Summary: Through the comparative analysis of the static pressure cloud map and the velocity cloud map of the new and old spool to the right by 5mm, we can know that for the static pressure cloud map, the throttle damping of the new valve is smaller than that of the old valve, which can reduce the loss of throttle energy In terms of velocity clouds, the maximum throttle speed of the new valve is less than the maximum throttle speed of the old valve, which means that at the same opening, its overflow area is slightly larger than that of the old valve.
