How is the discharge per unit found?

Q = P / (eta x 9.81 x H) = 5000/(0.88 x 9.81 x 80) = 7.24 m^3/s

Q = P / (9.81 x H) = 6.37 m^3/s

Which is the correct order of the water path through a unit?

Penstock, MIV, spiral casing, runner, draft tube

Draft tube, runner, spiral casing, MIV, penstock

Penstock, draft tube, runner, MIV

Spiral casing, penstock, MIV, draft tube

What approximate building dimensions are given?

Length 22 m, breadth 11 m, height 14 m

Length 11 m, breadth 22 m, height 5 m

Length 50 m, breadth 30 m, height 30 m

Length 14 m, breadth 14 m, height 22 m

2073 Shrawan · 4 marks

Powerhouse plan and sections (Francis, 10 MW)

Short answer

For 10 MW with two 5 MW units at 80 m head, flow is about 7.24 m3/s per unit, runner diameter about 1.06 m. The powerhouse plan has two units plus erection bay, length about 22 m, breadth about 11 m, height about 14 m; section shows penstock, valve, spiral casing, runner, draft tube, generator, crane and control room.

Draw plan and sections of a powerhouse showing various components. Assume a Francis turbine is used in this powerhouse to generate electricity of 10 MW.

Assumptions

Total 10 MW with 2 units of 5 MW each, net head 80 m, vertical-shaft Francis turbines, $\eta_o = 0.88$ .

Q = \frac{5000}{0.88 \times 9.81 \times 80} = 7.24\ \text{m}^3/\text{s per unit}

Rated speed 500 rpm ( $N_s \approx 148$ ) and runner diameter $D \approx 1.06$ m.

Plan

  <-------------- 22 m --------------->
  +-----------------------------------+ ^
  | Unit 1     Unit 2     Erection   | |
  |  (G)        (G)         bay      | 11 m
  |  MIV        MIV      (loading)   | |
  +--||----------||-------------------+ v
   Penstock     Control + switchgear room
   -> Draft tubes -> tailrace

Section A-A (through one unit)

   roof truss  ========================
   crane rail  --- EOT crane ---
   |            GENERATOR             |  generator floor
   |__________  exciter  ____________|
   |      Turbine floor / governor    |
   |   Spiral casing ( runner )       |
 ~~|~~~~~~~~~~~ draft tube ~~~~~~~~~~~|~~ tailwater
   foundation raft
 penstock -> MIV -> spiral casing

Components shown

Penstock, main inlet valve, spiral casing, stay ring, guide vanes, runner and draft tube.
Generator, exciter and governor.
Overhead crane (about 30 t, lifting the rotor), erection bay and loading area.
Control room, switchgear, battery room, workshop and office; transformers outside.
Approximate dimensions: length about 22 m, breadth about 11 m, height about 14 m (draft tube floor to roof).

✓ Answer checked by Claude Opus 5.5 (high effort)

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Powerhouse plan and sections (Francis, 10 MW)

Assumptions

Plan

Section A-A (through one unit)

Components shown

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