Fth5 Steam Engine Test, Lab Report Example

Introduction

The invention of the steam engine, invented by James Watt, during the industrial revolution was the beginning of modern technology. Steam engines were the standard technology used during the 18^th century in order to produce large quantities of power and in fact, 75% of the power produced today uses steam cycles. These include nuclear power plants and geothermal energy conversions. (Struchtrup, 1) Since the invention, the efficiency of steam engines has been researched and improved through the development of thermodynamics. The average thermal efficiency of steam power plants is 36% in North America. If the steam engines are combined with gas turbine cycles, the turbine exhaust increases the efficiency to 60% since it provides heat to the steam generator. (Sturchtrup, 1) Laboratory experiments are constantly performed in order to get a basic understanding of the heat engine, as well as to understand and calculate the cycle efficiency. The goal of this laboratory experiment was to observe an actual model for steam power and evaluate how the heat engine performs and the requirements that are needed in order for the heat engine to extract heat from a hot source and reject heat to a cold sink in order to produce a work output. In addition, the goal was to understand how to calculate the cycle efficiency, as well as gain experience using steam as a working fluid. (Laboratory Experiment FTH5, 1)

Methods

The Stuart ‘Sirius’ motor with twin ingle acting cylinders was used in the experiment. There were three main functions that were assigned to individual laboratory partner. One person was in charge of making sure that the water level in the boiler did not fall before the level on the glass gauge. One individual was assigned to refill the oil lubrication in the upper cylinder of the steam motor every 15 minutes. At the end of each 15 minutes the steam valve on the top of boiler B was closed, the oil filler cap C was loosened, the drain cock D was unscrewed and re-tightened, the oil filler cap C was removed, the steam regulator valve E was closed, oil was re-filled in the oil filler cap and the steam regulator valve was opened one half turn. Another individual was in charge of controlling the pressure in the boiler by turning the heaters on and off. This individual made sure that the boiler did not exceed 300 kN/m2 gauge.

Two tests were performed. The performance of the motor was evaluated and maintained by filling the boiler to the top mark on the level gauge. The spring balances were adjusted regularly. When the pressure reached 40 kN/m2, the steam valve was opened and the engine was turned over. The steam pressure was observed to reach 1800 rev/min and the following measurements were taken and calcuated: quantity, pressure, average engine speed, load, Initial electricity meter reading, Final electricity meter reading, Electrical Work in = Final – Initial, Coolant Temp In, Coolant Temp Out, Coolant Temp Difference = Out-In, Coolant volumentric flow rate, Coolant mass flow rate.

 Results

The results of the experiment are illustrated in Table 1, 2, 3, and 4. Two tests were performed to compare results for thermal power, work, efficiency and heat lost. The results for test 1 were 34.9% efficiency and 29.3% for test 2 (Table 2 and Table 4). The heat lost for test 1 was 1490.49 W and 1003.0 W for test 2.

 Table 1. Test 1 Measurements.

 Table 2. Calculations for Thermal Power, Work, Efficiency and Heat Lost During Test 1.

 Table 3. Test 2 Measurements

Table 4. Calculations for Thermal Power, Work, Efficiency and Heat Lost During Test 2.

Discussion

A steam engine is a device that converts thermal energy from pressurized steam into work. In the current experiment, a Stuart Sirius Steam Engine was used as the steam engine source. The device worked according to the laws of thermodynamics, such that the heat energy that is supplied to the system, exhibits a change in the internal energy and the change in work is done by the system against external forces (Laws of Thermodynamics 1). In this motor, the as the gas in the cylinder expands, the force exerted by the gas on the piston moves and the high pressure steam flows into the left hand cylinder to force the piston down. (Laboratory Experiment FTH5, 1) Therefore, in this equipment the heat source is the steam and the heat sink is the piston.

A closed cycle has equal initial and final states; therefore, the heat exchanged during a closed cycle must equal the amount of work that was completed. (Thermodynamics) In order for a closed cycle to occur, the heat engine must operate with two constant-temperature reservoirs. (Thermodynamics) In the current experiment, there were changes in the temperature reservoirs.

There are many different factors that can affect the performance or efficiency of a thermal power device, such as cycle arrangement, inlet and exhaust steam conditions, and the motor itself. Ultimately, the performance or efficiency is determined by the steam components such as the valves or caps. (Advances in Steam Path Technolgoy, 1) In the current experiment, the efficiency that was calculated was 34.9% and 23.9%. This means that the steam engine can only convert 34.9% and 23.9% of the heat into usable work. This is a low efficiency percentage because steam engines have a loss of heat due to the large exposed surface and it is not possible to maintain steam at high temperatures. (National Council of Research and Education) The loss of heat was observed in both tests that were run. Since there is such a low efficiency percentage for steam engines, there is constant research into developing steam engine devices with different cycles to increase the efficiency percentage.

Works Cited

CliffNotes. 2012. The Laws of Thermodynamics. Web. Retrieved on April 19, 2012 from: http://www.cliffsnotes.com/study_guide/The-Laws-of-Thermodynamics.topicArticleId-10453,articleId-10429.html

Cofer, J., Reinker, J., Sumner, W. Advances in Steam Path Technology. GE Power Systems GER-3713E. 40pgs.

National Council of Research and Education. Combustion Engine. Web. Retrieved on April 19, 2012 from: http://www.ncert.nic.in/html/learning_basket/energy10class/combustion%20engine1.htm

Struchtrup, H. 2005. University of Victoria Department of Mechanical Engineering. MECH 390 Laboratoy 2 Steam Engine. 5 pgs.

Thermodynamics. Web. Retrieved on April 19, 2012 from: http://www.innovatia.com/Design_Center/rktprop1.htm

University of Birmingham Mechanical Engineering. Laboratory Experiment FTH5. Steam Engine Test.