式中的系数a1、b1、a2、b2可由式(1 - 69)计算得到。
按照两泵串联后的总扬程等于两泵在同一流量时的扬程之和,即Q=Ql=Qll时Hl+ll= Hl+ Hll的原则，有:则两台相同泵串联后的特性方程为:
h2=h3, Q=Q1=Q2 + Q3
h=h1 +h2或h=h1 + h3
h= H,Q1 =Q渣浆泵厂家
Analytical method of slurry pump in series
Two centrifugal pumps are designed to work in series, and several groups of head and flow data are obtained from the measured data of two pumps or the points on the pump characteristic curve. The characteristic equations of pumps are obtained by least square regression
The coefficients A1, B1, A2 and B2 in the formula can be calculated by formula (1-69).
According to the principle that the total head of two pumps in series is equal to the sum of the heads of two pumps at the same flow, that is, when q = QL = QLL, HL + ll = HL + HL, the characteristic equation of two pumps in series is as follows:
The working point of the system can be obtained by combining it with the characteristic equation of pipeline. Several centrifugal pumps in series can also be calculated according to this principle.
3. Determination of working point of complex pipeline system
For the complex pipeline system, according to the hydraulic characteristics, the pressure at the crossing point of the pipeline is equal in parallel, and the total flow is equal to the sum of the flow of each branch pipe; the flow of each pipe section is equal in series, and the total friction is equal to the sum of the friction of each pipe section for superposition. For the intersection and branch pipeline system, the solution process is as follows.
1) Device characteristics of pump working on branch pipeline
When oil products are transported to one or several places at the same time through one pump (or several pumps applying for connection or parallel connection), branch pipeline shall be adopted for operation, as shown in Fig. 1-48 (a). The oil is pumped by tube 1 and then transported to two oil tanks along tube 2 and tube 3 respectively. The elevation difference of the three oil tanks to the pump axis is Z1, Z2 and Z3.
(1) Graphic method.
Draw the characteristics of suction line (H-Q) 1 and discharge line (H-Q) 2 and (H-Q) 3. Because tube 2 and tube 3 work in parallel, it is necessary to add the characteristics (H-Q) 2 + 3 in parallel. Then add (H-Q) 1 in series to get the total pipeline characteristic (H-Q) at of the whole pipeline system. It intersects the performance curve H-Q of the pump at point m, which is the working point of the branch pipeline.
The corresponding flow QW at point m is the flow Q in tube 1. In order to determine the flow in pipe 2 and pipe 3, make a vertical line through point m to intersect with the pipeline characteristic (H-Q) 2 + 3 at point a, lead the horizontal line from point a to intersect with (H q) 2 at point 2, and intersect with (H-Q) 3 at point 3, then the corresponding flow Q2 and Q3 at point 2 and point 3 are the flow in pipe 2 and pipe 3, and QM = QA = Q2 + Q3 = Q1.
(2) Analytical method.
Several groups of head and flow data are obtained from the measured pump or the points on the pump characteristic curve. The characteristic equation of the pump is h = a-bq2 by least square regression. The coefficients a and B can be calculated by formula (1-69).
The characteristic equation of pipeline 1 is as follows:
The characteristic equation of pipeline 2 is:
The characteristic equation of pipeline 3 is as follows:
Pipeline 2 and pipeline 3 are connected in parallel and then in series with pipeline 1. According to the principle of pipeline parallel connection, they are as follows:
h2=h3, Q=Q1=Q2 + Q3
The general characteristics of the pipeline are:
H = H1 + H2 or H = H1 + H3
For the system:
H = h, Q1 = q slurry pump manufacturer
Q1, Q2 and Q3 can be obtained by solving the equations.