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No. Dokumen:TB/MP/T3/BMCY3911/1

No. Isu/Tarikh:1/12-12-2007

COMBUSTION LABORATORYTwo-Shaft Gas Turbine

No. Semakan/Tarikh:2/28-06-2008

Jum. Mukasurat:5

OBJECTIVES

1. To describe the application concept of two-shaft gas turbine.2. To determine the shaft power and fuel consumption of the two-shaft gas turbine.3. To observe and evaluate the turbine characteristic.

LEARNING OUTCOMES

At the end of this laboratory session, students should be able to:1. Enhance understanding of the two-shaft gas turbine basic principles.2. Analyze the main characterictics of two-shaft gas turbine operation. 3. Gain experience on two-shaft gas turbine that widely used in the industry and the

thermodynamics engineering principles involved.4. Write the laboratory report according to a standard that describes the two-shaft

gas turbine by individually and team work.

THEORY

Gas turbine plant is used to generate mechanical and electrical energy as follows: For driving generators in power stations, For driving compressors and pumps in oil and gas extraction, For propelling ships, locomotives and heavy vehicles, For the propulsion of aircraft with propeller and jet engines.

Gas turbines are always used in situations where high power density, low weight and rapid start up are required. As fluid flow machines, gas turbines provide high flow rates for small machine dimensions unlike piston engines. This allows drives to be realised that are both light, and at the same time powerful.

As the moving parts in a gas turbine are only subject to rotary motion, given good balancing, almost vibration-free running is possible. The disadvantage is the high noise level caused by the high gas speeds and the simultaneous direct link to the atmosphere.

In comparison to steam turbines, gas turbines work at higher temperatures but lower pressures. The high temperatures, especially in the area of the turbine, require special high temperature materials.

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

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Figure 1 Educational Two-Shaft Gas Turbine

PROCEDURES

1. First, check the oil level and open propane gas valve on cylinder tank.2. Check the pipe work for leaks, open cooling water connection and check outlet of the

cooling water.3. Set load adjuster to zero.4. Connect all the mains power and switch them on.5. Check function of the temperature and speed indicators.6. Switch on starter fan and change over flap for starting air to ON.7. After 10 sec, operate ignition button and adjust the combustion gas flow rate to

around 30 % using control valve at the same time.8. During ignition, keep the button pressed down until turbine inlet temperature is above

T3 = 600 oC, then the ignition button can be released.9. Run up the turbine to the self-sustaining speed of n1 = 70000 rpm by adjusting the

fuel gas flow rate (T3 must not more than 1000 oC).10. Set starting air flap to OFF and switch off starter fan.11. Read the measured values from the designated points and fill them on Table 1.12. Repeat step 10 again base on Table 1.

FORMULA FOR CALCULATIONS

airairair VAm (1)

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where airm = air mass flow rate (kg/s)

air = air density (1.199 kg/m3)A = intake area of air (0.0038 m2)

airV

= air velocity (m/s)

100

)(

3600

4.10 G

TP

PPTm

gasgas

atmDogas

(2)

where gasm = gas mass flow rate (kg/s)

oT = room temperature (K)

DP = gas nozzle pressure (bar)

G = gas flow rate (%)

gasP = gas feeder pressure (bar)

gasT = gas temperature (K)

gas

air

m

m

L

min

1 (3)

where = air ratiominL = the amount of air for burning propane (15.23 /air gaskg kg )

)( 3232 PPPP (4)

electric

electricT

P

TP

273

288

12 (5)

where 2TP = turbine power output (W)

electricP = electrical power (W)

electric = efficiency of the generator (74%)

32 10

6.3

T

gasfuel P

mb

(6)

where fuelb = Specific fuel consumption (kg/kWh)

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EXPERIMENT DATA

Room Temperature (K) : ______________Atmospheric Pressure, Patm (bar) : ________

Table 1

No. Test 1 2 3

G [%] 35 40 45Generator load 3 3 3

T1 (oC)T2 (oC)T3 (oC)T4 (oC)T5 (oC)

Tgas (oC)

airV

(m/s)

P2 P3 (bar)P3 (bar)P4 (bar)PD (bar)Pgas (bar)

Turbine 1 speed, n1 (rpm)

Turbine 2 speed, n2 (rpm)

Pelectric (W)

EXPERIMENTAL RESULTSTable 2

No. Test 1 2 3G (%) 35 40 45

airm (kg/s)

gasm (kg/s)

P2 (bar)

2TP (W)

fuelb (kg/kWh)

SAMPLE CALCULATIONSGive some samples of calculation.

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DISCUSSION

1. Explain why the temperatures and the pressures of gas are decreasing after flowing out from turbine 1 & 2 (T3 > T4 > T5) & (P2 > P3 > P4)?

2. Why the speed of turbine 1 is faster then turbine 2? Explain.3. What is the relationship between gas flow rate, G and :

a. air velocity, airV

due to the air mass flow rate, airm

b. gas mass flow rate, gasm

c. air ratio, d. turbine power output, 2TP

e. specific fuel consumption, fuelb

4. What are the values for the shaft power and fuel consumption in each test?5. In overall, what can be concluded regarding the turbine characteristic?

QUESTIONS (FORMAL REPORT ONLY)

1. What are the suitable ways to improve gas turbine cycle efficiency?2. State the industrial application of two-shaft gas turbine.

CONCLUSIONConclude your finding.