Lab Report (5,500 words)

• Introduction
• Background
• Assumptions
• Objectives
• Measurements Procedures
• Calculations
• Conclusions

Assessment Cover Sheet and Feedback Form 2016/17

 

Module Code: NG1H201	Module Title: Thermodynamics 1		Module Lecturer:
Assignment Title: Application of the Steady Flow Energy Equation to an air flow through a heated duct			Assessment No. 1
No. of pages submitted in total including this page: Completed by student			Word Count of submission (if applicable): 1500 words±10%
Date Set: Refer to laboratory timetable		Submission Date: Refer to laboratory timetable	Return Date:

 

 

Part B: Marking and Assessment (to be completed by Module Lecturer)

This assignment will be marked out of 100%   This assignment contributes to 100% of the total module marks.

Assessment Title: – Application of Steady-Flow Energy Equation to Air Flow Through a Heated Duct         Tasks:            Refer to assignment briefs on Page 5

Learning Outcomes to be assessed (as specified in the validated module descriptor   Learning outcome 1: Understand thermodynamic systems involving perfect gases from the basic concepts using appropriate analytical models.   Learning outcome 2: Apply basic knowledge of thermodynamics in controlled laboratory environment.

 

Plant Description:-

The schematic diagram below illustrates a steady-flow test facility designed for the study of first law of thermodynamics. A centrifugal fan, driven by a fan motor, draws air into the test pipe at an elevation Z₁ and flow steadily until it is discharged at the air outlet at an elevation Z₂. An orifice meter is installed to measure the pressure drop across it from which the air mass flow rate () could be determined. As the air further flows pass the heater section, its temperature is increased before finally being discharged to the surroundings. The overall system boundary is denoted by the dotted line and there is an unknown heat transfer () between the system and the surroundings.

For this test assume air is an ideal gas:-

Density of air (p) = 1.2 kg/m³

Specific heat capacity of air (c_p) = 1.005 kJ/kg.k

Orifice diameter (d_o) = 40 mm

Figure 1: Schematic diagram of the experimental facility

Measurement Procedure:-

Equipment provided: Measuring tape, digital vernier calliper.

Wait until all readings are steady then record all the information necessary to carry out the objectives.

Plant Measurements

Examination of air flow in a heated duct	Test Observations
Air Temperature at inlet t1 [°C]	20.7 C
Air Temperature at outlet t2 [°C]	63.2 C
Pressure difference across orifice DHo [cm water gauge]	50 mm
Height of air inlet above datum line Z1 [m]	60 cm
Height of air outlet above datum line Z2 [m]	148.5 cm
Diameter of circumferential air inlet d1 [m]	130 mm
Width of circumferential air inlet w1[m]	14.4 mm
Diameter of air outlet pipe d2 [m]	32.6 mm
Heater Voltage VH [volts]	145 v
Heater Current AH [amperes]	3 A
Fan Motor voltage VF [volts]	415
Fan motor current AF [amperes]	2.35

 

Useful Formula:-

1. AIR MASS FLOW RATE, [kg/s]

WHERE,                                                                                                          [N/m²]

 

 

2. AIR INLET AREA, [m²]

 

3. AIR EXIT AREA,                 [m²]
4. VELOCITY OF AIR AT INLET,                 [m/s]

 

5. VELOCITY OF AIR AT OUTLET, [m/s]

 

6. POWER OF FAN, W_F = V_F ´ A_F                                                                            [W]

 

7. POWER OF HEATER, W_H = V_H ´ A_H                                                 [W]

Objectives:-

Use the values of plant measurements in the formula above to calculate the required parameters to the steady flow energy equation.

 

• Determine the unknown (as indicated in Figure 1) in magnitude and direction as the heat transfer rate in kW across the boundary.

 

• Examine the relative importance of the right-hand terms, i.e., , , of the steady-flow energy equation.

Write a report detailing the calculations and analysis of results and draw appropriate conclusions at the end.

Guidelines for writing lab report

Introduction

The intention of any scientific Introduction is to establish the purpose for doing the experiment that is to be reported. An effective introduction to a lab report typically performs the following tasks, generally in the order presented:

1. it establishes the learning context for the lab by:
   1. stating what the lab is about, why was this experiment performed and why is it relevant?
   2. With the aid of a schematic diagram of the system, describe the necessary background theory and explain it in the context of the experiment conducted. This would help reader to better understand the theoretical aspects of the experiment and the hypotheses.
2. it provides the primary goals of the lab by presenting the objective(s) of the experiments. The objectives of the experiment are important to state because their outcomes will be analysed in the conclusion.

Measurement procedures

This section should include brief description of the system under investigation and conditions for the experiments. With the aid of a schematic diagram of the system you should explain how measurements were taken.

Results and Discussion

The result section should contain raw data.  Raw data consist of actual measured values recorded during the experiment.  Use Table(s) to present this information.  All tables should have descriptive titles, and they should show the units of data entries clearly. Results from further analyses of the raw data should also be included in this section. In discussing the results, you should not only analyse the results, but also discuss the implications of those results.

Conclusions

Whereas the “Results and Discussion” section has discussed the results individually, the “Conclusion” section summarises the results and findings in the context of the entire experiment. Usually, the objectives mentioned in the “Introduction” are examined to determine whether the experiment succeeded. If the objectives were not met, you should analyse why the results were not as predicted.

References

This is a list of the references that were cited in the lab report, including the lab manual (if any), any handouts accompanying the lab, the textbook, and sources from the scientific literature. Use Harvard referencing format.

Note:

This is the device we used for the experiment.

The result in blue colour in the table are measured by the student using Measuring tape, digital Vernier calliper from the floor to the centre of each point to measure:

The inlet temperature was given 20.7

Air Temperature at inlet t1 [°C]	20.7 C
Air Temperature at outlet t2 [°C]	63.2 C
Pressure difference across orifice DHo [cm water gauge]	50 mm
Height of air inlet above datum line Z1 [m]	60 cm
Height of air outlet above datum line Z2 [m]	148.5 cm
Diameter of circumferential air inlet d1 [m]	130 mm
Width of circumferential air inlet w1[m]	14.4 mm
Diameter of air outlet pipe d2 [m]	32.6 mm
Heater Voltage VH [volts]	145 v
Heater Current AH [amperes]	3 A