Thermodynamics Lab Report

Assignment 2: (Laboratory Project)

Laboratories 1 and 2: Internal combustion engine efficiency

Summary

The experiment was aimed at showing how pump selection can be done using characteristic performance curves. The motivation behind this trial is to look at the execution and attributes of a diffusive pump, its engine, and the comparing channeling framework, used to pump water. The pump utilized within this test has an execution bend focused around water, so pump execution bends, and in addition engine execution bends, will be created over an extensive variety of stream rates to focus the impact that the fluid consistency and thickness have on the execution of this pump.

More specifically, the results of the experiment should give the performances of a number of motors and pumps from a thermodynamic point of view. Pump curves can be used to a specific flow rate and head requirement. A centrifugal pump characteristic curve represents the flow rate versus the head achieved for different pumps with different impeller diameters. In addition to evaluating the flow vs. head performance curves, the efficiencies of and the Brake Horsepower are also evaluated. The desire flo-w rate and head points are first plotted. The impeller diameter, Brake Horsepower and the efficiency can then be evaluated. During the experiment, it was established that the efficiency of a pump varies throughout its operating range. A greater head is required for higher flow rates.

The performance curves present the relationship of the capacity, head, and horsepower of the pumps in a much easier and satisfactory way. The curves are developed given a specific rotational speed and impeller size.

Equipments

The above diagram shows the set-up of the system. Two engines and three pumps were used. The specifications of the two engines are as shown.

Engine 1: 232 cc, 4 stroke diesel motor

Engine 2: 172 cc, 4 strokes petrol engine

Other equipments required during the experiment included:

· Test beds

· Dynamometers

Results

From the formula

And given that D = 35mm = 0.035 m, then

Duty points can be found by drawing the above equation on the characteristic curve. It is given by the points of intersection of equation and the characteristic curves.

Pump A

· Flow rate = 5.1 m3/hr

· Head = 31 m

· Pump efficiency = 50%

Pump B

· Flow rate = 4.1 m3/hr

· Head = 25 m

· Pump efficiency = 55%

Pump C

· Flow rate = 2.8 m3/hr

· Head = 22 m

· Pump efficiency = 57%

Power required:

Pump A

Power = (5.1 *1000*9.81*31)/(3.6*10^6) = 0.430823kW

Pump B

Power = (4.1 *1000*9.81*25)/(3.6*10^6) = 0.2793kW

Pump C

Power = (2.8 *1000*9.81*22)/(3.6*10^6) = 0.16786kW

Engine	Diesel	Petrol
Noise (dB)	104 dB (2360 rpm, near muffler)	100 dB (2390 rpm, near muffler)
Pump:	A	B	C	A	B	C
Flow rate (kg/s) (water)	5.1	4.1	2.8
Pump Head (m)	31	25	22
Pump Efficiency	50	55	57
RPM	2320	2406	2360
Power Required from motor (N.m)	0.43082	0.2793	0.16786
Can engine deliver required power?	yes	yes	yes
Thermal efficiency of engine (%)
Time needed to pump 25000L of water (L)	22	22.2	22.5	68	62	55
No. of litres of fuel required to pump 25000L of water	8	8	8	8	8	8
Cost of fuel required to pump 25000L of water (J)
Increase in potential energy of 25000L of water (J)	3188.25kJ	3188.25kJ	3188.25kJ	3188.25kJ	3188.25kJ	3188.25kJ
Energy used by motor to fill the tank (J)
Overall thermal efficiency of the system
Air/Fuel ratio
Mass of CO2 produced by pumping 25000L of water (kg)
Recommended pump/motor combination

Analysis

From the results of the experiment above, it is clear that characteristics of pumps vary with various conditions. The properties of a pump can therefore be defined using characteristic curves. The shape or size of a pump cannot give sufficient information regarding the properties of the pump. From the pump characteristic curves, the variation of head and flow rate is studied.

The main purpose of the experiment was to draw the characteristic curve having the conditions such as the head, power required, and the flow rate. The efficiency must be compromised in order to achieve the actual field conditions. The characteristic field helps in optimizing these field conditions that enabled us to select a particular pump that gives the best performance.

Y-Values 0 4 6 7.5 9 12 14.7 16 22 21.6 21.5 21 20 17.5 15 13.5 X-Values2 0 4 6 7.5 9 12 14.7 16 25 24.9 24.5 24.4 23.7 22 20 18.399999999999999 Y-Values2 0 4 6 7.5 9 12 14.7 16 31 30.9 30.6 30.4 29.9 28.8 27 25.8 X-Values3 0 4 6 7.5 9 12 14.7 16 15 24.88 37.220000000000013 Y-Values3 0 4 6 7.5 9 12 14.7 16 X-Values4 0 4 6 7.5 9 12 14.7 16 Y-Values4 0 4 6 7.5 9 12 14.7 16