Principles of Turbomachinery in Air-Breathing Engines by Erian A. Baskharone | 9780521858106 | 0521858100 | Holooly

Aircraft Design

Principles of Turbomachinery in Air-Breathing Engines

59 SOLVED PROBLEMS

Question: 11.4

Figure 11.23 shows a centrifugal compressor stage that is geometrically identical to that in Example 3. The impeller is radial, meaning there is no appreciable axial velocity component anywhere within this subdomain. The stage operating conditions are as follows: Inlet total pressure ...

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Part a: Knowing that the stage-inlet swirl angle (...

Question: 11.2

Figure 11.21 shows a centrifugal compressor stage, which is equipped with a totally radial impeller (i.e., one with no appreciable axial-velocity component anywhere). The stage geometrical data and operating conditions are as follows: Mass-flow rate (m) = 2.5 kg/s Shaft speed (N) = 22,000 rpm ...

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Part a: Let us begin by computing the impeller-inl...

Question: 11.1

The design point of a centrifugal-compressor stage (shown in Fig. 11.20) is defined as follows: Inlet total pressure (pt 1) = 1.08 bars Inlet total temperature (Tt 1) = 302 K Mass-flow rate (m) = 5.2 kg/s Shaft speed (N) = 12, 000 rpm Inlet absolute velocity is totally axial Inlet critical Mach ...

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Part a: Let us begin by computing the impeller-inl...

Question: 12.6

Figure 12.18 shows the compressor and turbine maps for a turbojet engine. The following variables are assumed fixed under all viable modes of operation: Combustor total-to-total pressure ratio (pt 4/pt 3) = 0.94 Fuel-to-air ratio (f) = 0.024 System mechanical efficiency (ηm) = 97% Beginning with an ...

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OUTER LOOP Step 1: Let us arbitrarily pick a point...

Question: 12.5

Figure 12.17 shows the turbine and compressor maps for a single-spool no-load gas turbine engine. The engine is operating under the following conditions: Fuel-to-air ratio ( f ) = 0.024 Mechanical efficiency (ηm) = 0.95% Select any reasonable magnitude for the Tt 4/Tt 2 ratio. Now select a point on ...

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Let us arbitrarily set the ratio (

T_{t\ 4}/...

Question: 12.4

The compressor and turbine maps of a turbojet engine are shown in Figure 12.16, with the latter carrying the turbine operation point (circled on the map). The engine cruise operation is defined as follows: Ambient pressure (p1) = 0.21 bars Ambient temperature (T1) = 218 K Flight Mach number ...

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Let us first calculate the compressor-inlet total ...

Question: 12.3

Figure 12.15 shows the compressor and turbine maps in a simple turbojet engine. The engine design point is its 11.3 km (37,000 ft) cruise operation, where the flight Mach number is 0.71. The ambient pressure and temperature at this altitude, are 0.21 bars and 218 K, respectively. The compressor ...

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Using the compressor map, we get

N_{C2}=44,...

Question: 12.2

Figure 12.14 shows a single-stage axial-flow compressor together with its map and major dimensions. The compressor operating conditions are as follows: Physical mass-flow rate (m) = 1.5 kg/s Stage-inlet total pressure (pt 1) = 0.25 bars Stage-inlet total temperature (Tt 1) = 200 K Stator flow ...

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Part a: Because the stator flow is given as isentr...

Question: 12.1

The cruise operation of a single-spool turbojet engine (Fig. 12.13) is defined as follows: Flight Mach number (M1) = 0.85 Ambient temperature (T1) = 251.6 K Ambient pressure (p1) = 0.45 bars Shaft speed (N) = 34,000 rpm Turbine-inlet total temperature (Tt4) = 1152 K Combustor total-to-total ...

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Part Ia:

T_{t\ 2}=T_{1}\biggl[1+\biggl(\fra...

Question: 11.6

The objective of this example is to numerically verify the theoretical rationale with which the “slip-phenomenon” section was introduced. The computational procedure here is consistent with this rationale. In other words, we will calculate each of the centripetal and Coriolis acceleration ...

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Referring to the inlet velocity diagram in Figure ...

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