Assignment 2

Gear pump sucks the gas up from the subterranean gas storage and brings it into two fuel fillers.

Fig.2. Schematic diagram of the fuel supply: 1 – fuel-filler; 2 – non-return valve; 3 – filter; 4 – gear pump; 5 – gas tank; 6 – manometer

Determine:

1.The absolute pressure P₁ at the entrance of the pump, if the pump deliver is Q, pipeline length is l₁, its diameter is d₁, gage pressure in the gas storage is P = const.

2. Required head of the pump, if gage pressure in point A is equal to P₂, length of the pipeline is l₂, its diameter is d₂.

3. Diameters of the pipelines d₃ and d₄, when minimal positional heights of the tanks are h₃ and h₄.

4. Time t of tanks filling.

Gas viscosity coefficient is ν, gas specific weight is γ, local resistances, set in the pipelines are shown in the schematic diagram. The height of liquid column in tanks is neglected. Atmospheric pressure is 760 mm of mercury head.

Solution technique:

1. Determine Re-number, λ, Σh, using the given data of Q, d, and l_1. Pipeline length on a straight segment let be equal to h₁.

2. Calculate the pressure at the entrance of the pump, using the data of h₁, P and Σh.

3. Determine the flow velocity V of liquid, then Re-number, and the resistance coefficient λ, using assigned consumptions Q and assigned diameter of pipeline d₂.

4. Calculate the head losses from the gear pump to the triple (point A). Assigned data of local resistance coefficients should be taken from table [1].

5. Using given data of P₂, h₂, and Σh, calculate the head H_{1 req}.

6. Using given data of W_1, W₂, determine the fuel consumption in each tank.

7. Setting the data row of d₃ and d₄, calculate the gas flow velocity in the pipeline, Re-number, resistance coefficient λ.

8. Calculate the required head value H for each of d₃ and build the dependence diagram H=f (d₃).

9. Using the available head, determine d₃ and d₄ then choose the standard one.

10. Calculate time t, using the value of pump deliver and total volume.

Table 2