2024年3月24日发(作者：臧清一)

汽轮机原理（Turbine principle）

Including the working principle of the steam turbine stage and

the working principle of the whole steam turbine unit. The

working principle of a steam turbine involves the flow of steam,

the generation of forces on the blades and the formation of

losses, and the method of adapting the turbine to changes in

the external load. 1 O2 P _* `$N: N I* W!

The working principle of the stage is converted to mechanical

work in the steam turbine stage according to the energy

contained in the steam. The stage of the steam turbine can be

divided into 3 kinds, namely, impulse, reaction and velocity.

& S&, W2}, ` H8, t, U3, P, impulse, level 2, schematic diagram

of the impulse level. The steam expands in the nozzle and the

pressure drops from the inlet P0 to the P1 at the exit (Figure

2A). As the cross-sectional area of the nozzle channel

decreases gradually (Fig. 2b), the velocity of steam in the

nozzle increases gradually. The energy contained in the steam

is converted to the kinetic energy of the steam stream. The

absolute velocity is C1 at the nozzle and the steam flow angle

is alpha 1. Since the circumferential velocity of the moving

blade is u, the relative velocity of the steam entering the

moving blade is W1, and the steam flow angle is 1. There is no

change in the pressure when the steam flows through the moving

blades, that is, the pressure at the moving blade exit is equal

to the pressure of the inlet P2 p1. The relative velocity of

the moving blade exit is w 2, the steam flow angle is 2, the

absolute velocity is C2, and the steam flow angle is alpha 2

(Figure 2C). When the steam passes through the moving blade,

the direction changes, and the momentum of the steam stream

changes, thus acting on the moving blade and driving the rotor

to rotate. The leaves of the impulse moving leaves are close

to the right and left symmetry. In the inlet and outlet of the

nozzle and the moving blade, the magnitude and direction of the

steam flow velocity can be represented by the size and direction

of the vector segment in a certain proportion. These vector

segments constitute the so-called velocity triangle.

X/ b-]1 c& Q # "D5 K3 X B D)"

(H8, H0, Z5, W6, E%, f% ^) u, Y

8 S4 D% T7 T: Q'B O in the enthalpy H as ordinate, with entropy

S as abscissa of H-S diagram (Figure 2D), from the nozzle inlet

steam point to the stage after the static pressure P2 as an

isentropic line p3. The enthalpy of the starting point of this

line is H 0, and the enthalpy at the end point is H 2. The

difference H0-H2=I0 is called isentropic enthalpy drop. Unit

is kJ / kg. When the isentropic enthalpy drop is converted to

the kinetic energy of the steam flow, the ideal speed of the

steam flow at the exit of the corresponding nozzle is obtained.

But in the nozzle flow loss, so the actual outlet steam flow

velocity C1 = C1t DTH DTH, called nozzle velocity coefficient,

generally 0.96 ~ 0.98. Similarly, due to flow loss, the relative

velocity of the moving blade outlet at w2=w1 is called the

moving blade velocity coefficient, which is generally 0.92 to

0.95. The steam flow rate and direction of change of mass flow

to produce steam passing through 1 kg / s when the blade wheel

force is Fu=c1cos alpha 1+c2cos alpha 2 Newton, the

corresponding power called wheel power Pu, or Hu u=Hu=Fu u, said

the enthalpy drop =u (c1cos alpha 1+c2cos alpha 2). In this way,

2024年3月24日发(作者：臧清一)

汽轮机原理（Turbine principle）

Including the working principle of the steam turbine stage and

the working principle of the whole steam turbine unit. The

working principle of a steam turbine involves the flow of steam,

the generation of forces on the blades and the formation of

losses, and the method of adapting the turbine to changes in

the external load. 1 O2 P _* `$N: N I* W!

The working principle of the stage is converted to mechanical

work in the steam turbine stage according to the energy

contained in the steam. The stage of the steam turbine can be

divided into 3 kinds, namely, impulse, reaction and velocity.

& S&, W2}, ` H8, t, U3, P, impulse, level 2, schematic diagram

of the impulse level. The steam expands in the nozzle and the

pressure drops from the inlet P0 to the P1 at the exit (Figure

2A). As the cross-sectional area of the nozzle channel

decreases gradually (Fig. 2b), the velocity of steam in the

nozzle increases gradually. The energy contained in the steam

is converted to the kinetic energy of the steam stream. The

absolute velocity is C1 at the nozzle and the steam flow angle

is alpha 1. Since the circumferential velocity of the moving

blade is u, the relative velocity of the steam entering the

moving blade is W1, and the steam flow angle is 1. There is no

change in the pressure when the steam flows through the moving

blades, that is, the pressure at the moving blade exit is equal

to the pressure of the inlet P2 p1. The relative velocity of

the moving blade exit is w 2, the steam flow angle is 2, the

absolute velocity is C2, and the steam flow angle is alpha 2

(Figure 2C). When the steam passes through the moving blade,

the direction changes, and the momentum of the steam stream

changes, thus acting on the moving blade and driving the rotor

to rotate. The leaves of the impulse moving leaves are close

to the right and left symmetry. In the inlet and outlet of the

nozzle and the moving blade, the magnitude and direction of the

steam flow velocity can be represented by the size and direction

of the vector segment in a certain proportion. These vector

segments constitute the so-called velocity triangle.

X/ b-]1 c& Q # "D5 K3 X B D)"

(H8, H0, Z5, W6, E%, f% ^) u, Y

8 S4 D% T7 T: Q'B O in the enthalpy H as ordinate, with entropy

S as abscissa of H-S diagram (Figure 2D), from the nozzle inlet

steam point to the stage after the static pressure P2 as an

isentropic line p3. The enthalpy of the starting point of this

line is H 0, and the enthalpy at the end point is H 2. The

difference H0-H2=I0 is called isentropic enthalpy drop. Unit

is kJ / kg. When the isentropic enthalpy drop is converted to

the kinetic energy of the steam flow, the ideal speed of the

steam flow at the exit of the corresponding nozzle is obtained.

But in the nozzle flow loss, so the actual outlet steam flow

velocity C1 = C1t DTH DTH, called nozzle velocity coefficient,

generally 0.96 ~ 0.98. Similarly, due to flow loss, the relative

velocity of the moving blade outlet at w2=w1 is called the

moving blade velocity coefficient, which is generally 0.92 to

0.95. The steam flow rate and direction of change of mass flow

to produce steam passing through 1 kg / s when the blade wheel

force is Fu=c1cos alpha 1+c2cos alpha 2 Newton, the

corresponding power called wheel power Pu, or Hu u=Hu=Fu u, said

the enthalpy drop =u (c1cos alpha 1+c2cos alpha 2). In this way,