2 Aerodynamics
123
where Ma is the local Mach number of the gas (=V /a, the a =
√
γ RT ).
Based on the one-dimensional steady compressible flow equation, the
quantitative relationship between the motion parameters and the static
parameters of each point can be established.
In 1889, Swedish engineer Karl Gustaf Patrik De Laval (1845–1913,
inventor of single-stage impact turbine, as shown in Fig. 2.58) successfully obtained the supersonic flow through the first contraction and then
expansion pipe, manufactured the impact steam turbine, and proposed
the famous pull valve nozzle. According to the continuous equation of
one-dimensional steady flow
dρ
ρ
+
dV
V
+
d A
A
= 0
Substituting the speed of sound a 2 =
d p
dρ into the momentum
equation, there are
dρ
ρ
= −Ma
2 dV
V
Fig. 2.58 Karl Gustaf Patrik de Laval (1845–1913, Swedish engineer)
123
where Ma is the local Mach number of the gas (=V /a, the a =
√
γ RT ).
Based on the one-dimensional steady compressible flow equation, the
quantitative relationship between the motion parameters and the static
parameters of each point can be established.
In 1889, Swedish engineer Karl Gustaf Patrik De Laval (1845–1913,
inventor of single-stage impact turbine, as shown in Fig. 2.58) successfully obtained the supersonic flow through the first contraction and then
expansion pipe, manufactured the impact steam turbine, and proposed
the famous pull valve nozzle. According to the continuous equation of
one-dimensional steady flow
dρ
ρ
+
dV
V
+
d A
A
= 0
Substituting the speed of sound a 2 =
d p
dρ into the momentum
equation, there are
dρ
ρ
= −Ma
2 dV
V
Fig. 2.58 Karl Gustaf Patrik de Laval (1845–1913, Swedish engineer)