CONCLUSION

 

The experiment is successful  because it have achieve its objective which is to determine the performance of steam engine such as engine torque, engine power output, steam consumption rate, engine brake power and specific steam consumption. From that we made increment of load will affected the performance of steam engine. Therefore, from the graph, we can conclude that each of these elements is related to each other since that every change of value of it will affect the others. 

DISCUSSION

 

From the data, five graphs have been plotted, which is the graph of engine torque, steam flow rate, engine inlet pressure, boiler pressure and specific steam consumption verses engine brake power. By referring to the first graph, it shows that the relation between engine torque and engine break power is proportional with each other. When force applied increase, the value of engine torque produced increase. As a result of increasing in engine torque produced, the values of engine break power also increase.

            According to the second graph, it shows that the graph between steam flow rate and engine break power is not linear. This is because the value of steam flow rate drop from 9 kg/h to 8.4 kg/h when the engine brake power reach 35.1858 kW.

From the third graph, we can see that the engine inlet pressure increase when engine break power increase. It shows that the engine inlet pressure and the engine break power are linear to each other. Although the value of engine inlet pressure increase not too much, but the steam engine still produce bigger brake power.

By referring to the fourth graph, it shows that the boiler pressure and the engine break power are not proportional to each other. We can see that the value of boiler pressure from first to third reading are linear but the fourth reading is constant with third reading and the fifth reading the value is drop.   

The last graph shows that the graph drop means that the value of specific steam consumption is decrease when the values of engine break power increase. This is because the value of specific steam consumption relates to steam flow rate (steam consumption rate) and engine break power.

 However, all the readings that obtained may not accurate because the efficiency of machine, low skills, room temperature and others. All this reasons could give effect on the readings. Besides that, error also occurs because the motor speed cannot be maintained constant.

GRAPH ANALYSIS

 

 

 

Engine Torque, T (Nm)	Steam Flow Rate, mf (kg/h)	Engine Inlet Pressure, P (kN/m2)	Boiler Pressure, E (kN/m2)	Specific Steam Consumption, SSC (kg/ kW.h)	Engine Break Power, Bp (kW)
0.056	6.0	180	360	0.682	8.7965
0.112	8.1	200	380	0.4604	17.5929
0.168	8.1	220	400	0.3069	26.3894
0.224	9	260	400	0.2558	35.1858
0.28	8.4	280	380	0.191	43.9823

 

Table 2

 

 

 

 

 

 

a )

 

 

b)

 

 

 

 

c)

 

 

 

d)

 

 

 

 

 

 

e)

 

SAMPLE OF CALCULATION :

 

a) Sample calculation for engine torque

 

Engine Torque, T = ( F₁ + F₂ )R

 

T₁ = (1.0) (0.056)

  = 0.056 Nm

 

T₂ = (2.0) (0.056)

     = 0.112 Nm

 

T₃ = (3.0) (0.056)

                 = 0.168 Nm

 

T₄ = (4.0) (0.056)

                 = 0.224 Nm

 

T₅ = (5.0) (0.056)

                 = 0.28 Nm

 

 

 

b) Sample calculation for engine break power

 

Engine Break Power, Bp = 2πNT

   60

 

Bp₁ =

                    

                   = 8.7965 KW

 

 

 

 

 

Bp₂ =

                   = 17.5929 KW

 

 

Bp₃ =

                   = 26.3894 KW

 

 

Bp₄ =

                   = 35.1858 KW

 

 

Bp₅ =

                   = 43.9823 KW

 

 

 

c) Sample calculation for steam flow rate

Steam Flow Rate (Steam Consumption Rate), m_f = flow rate x r

 

m_f1 = flow rate(condensation rate) x r

       = 100 x 10^-3 x (0.001 x 60) m³ x 1000 kg

                                                              h               m³

                  = 6.0 kg/h

 

 

 

m_f2  = 135 x 10^-3 x (0.001 x 60) m³ x 1000 kg

    h               m³

        = 8.1 kg/h

 

 

 

m_f3   = 135 x 10^-3 x (0.001 x 60) m³ x 1000 kg

                h               m³

                    = 8.1 kg/h

 

 

m_f4  = 150 x 10^-3 x (0.001 x 60) m³ x 1000 kg

                                                    h               m³

                    =  9 kg/h

 

 

m_f5  = 140 x 10^-3 x (0.001 x 60) m³ x 1000 kg

                            h               m³

                    = 8.4 kg/h

 

 

d) Sample calculation for specific steam consumption

 

Specific Steam Consumption, SSC =  m_f

                                                                  Bp

 

SSC₁ = m_f1

                        Bp₁

         =   6.0       

            8.7965

                     = 0.682 Kg/KW.h

 

 

SSC₂ = m_f2

                         Bp₂

         =    8.1

            17.5929

                     = 0.4604 Kg/KW.h

 

 

 

 

SSC₃ = m_f3

                        Bp₃

         =    8.1

            26.3894

         = 0.3069 Kg/KW.h

 

 

SSC₄ = m_f4

                        Bp₄

         =   9

            35.1858

         = 0.2558 Kg/KW.h

 

 

SSC₅ = m_f5

                        Bp₅

         =    8.4

                        43.9823

         = 0.191 Kg/KW.h

RESULTS

 

 

 

 

Load F; N (F1+F2)	Boiler Pressure E; kN/m2	Temperature of External water supply: ˚C		Motor speed (rpm)	Engine inlet pressure; kN/m2	Boiler Temperature; ˚C	Condensation Rate; mL/min	Condensation Temperature; ˚C	Calori-meter
		T in	T out
1.0	360	27.8	35.5	1500	180	149.9	100	38.5	54.9
2.0	380	27.9	36.2	1500	200	152.4	135	45	69.9
3.0	400	28.0	36.9	1500	220	152.2	135	45	74.5
4.0	400	28.4	38.4	1500	260	152.1	150	51	83.6
5.0	380	28.7	38.7	1500	280	152.0	140	50	87.8

 

Table 1

EXPERIMENT PROCEDURE

 

a)         The power supply is switched on.

b)         The feed water pump is switched on to allow water to flow from a reservoir into

boiler. The capacity input into the boiler should be in the minimum and maximum

level as indicated on the edge of the front boiler side or near to the front heater.

c)         There are two springs in the system. Either one is set as a datum. Then, spring

load of the other spring is set according to necessary load. In the first case the load is set to 0 N.

d)         Then the switch of the front and rear heater in the system is turned on.

c)         When the pressure in the boiler reaching about 3.5 bar (350 kN/m²), the actual

boiler pressure and temperature is read from the pressure meter and thermometer

attached.

f)          When the temperature has reached or more than 100 Celsius, the steam inside the

boiler is released by opening the steam control valve.

g)         In one swift movement, the starting knob is pulled upwards on and let go.

h)         Using tachometer, the steam motor rotation is adjust and try to maintain constant at about 1500 rpm by adjusting the steam control valve at the boiler.

i)          The condenser cooling water is turned on and adjusts to a flow rate of about 1.6

l/ min. The apparatus is run at least 5 minutes for condition to stable.

j)          The boiler pressure and temperature is recorded, engine inlet pressure , engine speed, spring balance loads, condenser cooling water temperatures and flow rate and condensate flow rate obtained at varying engine load to the table 1. The condensate flow rate is measured by measuring the volume collected in a measuring cylinder for a period of I minute.

k)         Step (J) is repeated for load 1.0N, 1.5N, 2.0N, 2.5N, 3.0N.

l)          After use, the electrical and water supplies is disconnect also allow the boiler to cool down and open the boiler drain valve. Any water from the apparatus is drained.

m)        The temperature display is switched off.

EQUIPMENT

 

An electric pump, electric boiler, small steam engine, a water cooled condenser unit, reservoir tank, the temperature instrument box, electric control panel, power supply, and thermometer.

 

OBJECTIVES

 

To determine the performance of the steam engine such as torque, engine power output, specific steam consumption and cycle efficiency.

 

 

4. THEORY

 

Criteria for performance can be calculated used below equations.

 

Engine torque, T = (F₁-F₂)R [Nm]

 

Engine break power, Bp = [kW]

Specific steam consumption, ssc =  [kg/kW.h]

 

 

where:

 

N = Engine speed                                             [rev/min]

F1 = The changes in the first load spring            [N]

F2 = The changes in the second load spring       [N]

R  = Radius of the pulley, 0.056                        [m]

M_f = steam consumption rate                            [kg/h]

 

RANKINE CYCLE

 

Saturated or superheated steam enters the turbine at state 1, where it expands isentropically to the exit pressure at state 2. The steam is then condensed at constant pressure and temperature to a saturated liquid, state 3. The heat removed from the steam in the condenser is typically transferred to the cooling water. The saturated liquid then flows through the pump which increases the pressure to the boiler pressure (state 4), where the water is first heated to the saturation temperature, boiled and typically superheated to state 1. Then the whole cycle is repeated.

Basic steam power plant

 

 

2. INTRODUCTION

 

The steam engine is a heat engine converting heat energy to work. The conversion is performed by a cycle of processes. Heat created externally by pump is transferred to water in a steam generating unit or boiler. The steam carries energy to the expander (engine), part of the heat energy is converted to mechanical energy, which is work. The steam leaves the expander and is condensed back to water at condenser, rejecting some heat energy. This is known as an external combustion engine. These processes must conform to the First Law of Thermodynamics expressed in the General Energy Equation. This cycle is called the Rankine cycle and is the accepted standard of comparison for steam plants today.

 

-Basic Steam Engine-