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-