Assignment 3

Working liquid АМG-10 (Fig.3.) is supplied by pump 2 from tank 1 into exchanger 5, where it is heated from temperature t₁ to temperature t₂. And then it goes to refrigerator 6 through two filters 4, installed in parallel, where it is cooled to temperature t₁, and returns to the consumption tank.

Data for calculation are given in the table (let l₁= h₁+0.6 m).

Determine:

1.Sucking pipeline diameter d₁.

2.Pressure P₃ produced by the pump.

3.Pump drive required power N_r.

Fig.3. Schematic diagram of the hydraulic system: 1 – consumption tank; 2 – pump; 3 – non-return valve; 4 – filter; 5 – exchanger with heat supply; 6 – refrigerator

Note: Exchanger 5 and refrigerator Local resistance coefficients of exchanger and refrigerator are equal to local resistance coefficients of measuring device and grid filter. The height of liquid column in the tank is ignored. The curve of kinematic viscosity of working liquid AMG-10 versus temperature is demonstrated in the Appendix [2].

Solution technique:

1. Determine sucking pipeline diameter d₁ using given data of Q, h₁, l₁, P₁, P₂, taking l₁= h₁+0.5 m.

2. Calculate the head losses at sector 2 up to the exchanger.

3. Calculate the head losses at sector 3, taking into account temperature changes of the liquid, up to the exchanger branching.

4. Calculate the head losses at sector 4, taking into account that the filters are installed in parallel.

5. Determine the head losses at the sectors 5 and 6, taking into account the height h₂, the pressure in the tank P₁, and the liquid temperature changes.

6. Summarize the head losses in the sectors; calculate pressure P₃ and the pump drive power N_r using efficiency η.

Table 3