Essay on Design of Machine Elements

Submitted By jay1491
Words: 8155
Pages: 33
Open Document
1.0 Introduction
The transfer of heat normally involves the change in temperature of an object with high temperature to another object with lower temperature. According to the First Law of Thermodynamics, heat transfer changes the internal energy of both systems involved.
As such, the three modes of heat transfer are; Conduction, Convection and Radiation. According to C.R. Nave (Hyper Physics, 2010), conduction is heat transfer by means of molecular agitation within a material without any motion of the material as a whole, convection is heat transfer by mass motion of a fluid such as air or water when the heated fluid is caused to move away from the source of heat, carrying energy with it and radiation is heat transfer by the emission of electromagnetic waves which carry energy away from the emitting object.
The aim of this laboratory exercise focus on conducting practical exercises to identify the variety of different heat transfer concepts involved and develops an understanding of their applications and functions.
As such, this laboratory report comes in 4 parts where the first 2 parts, will touch on practical exercise on heat transfer by radiation of a copper rod with blackened surface and heat transfer by natural convection of the same material respectively. The last 2 parts will touch on practical exercise on heat exchanger performance and heat losses in pipes respectively.
1.2 Equipment

* Copper rod with internal electric heating element * DC power supply * Pressure valve and vaccum pump * Thermocouple on surface of heated rod * Thermocouple on inside surface of pressure vessel wall * Digital pressure gauge (for low pressures < 10000 Pa absolute) * Digital pressure gauge (for vacuum gauge pressures up to atmospheric, in Bar) * Barometer * Heated Copper rod (L = .1 m, D = .018 m)

1.3 Procedure

1. Vacuum pump was run to remove as much air as was possible within the pressure vessel. a. This would result in absolute pressure <10 Pa but would be ideally closer to 5 Pa. 2. Electric heating element was activated and set to 9 Watts of input power, which was equivalent to 56% setting. 3. Thermal equilibrium was established after waiting a short duration. b. Surface temperature of the rod stopped changing. 4. Electric heat input the rod was recorded as the electric power supplied. 5. 5% was subtracted from the power due to power dissipation within the cables. 6. Other measurements were recorded; pressure in the vessel, temperature of the heated rod (T1) and also the temperature of the surrounding pressure vessel wall (T2). 7. A small amount of air was allowed to enter the pressure vessel through the inlet valve (WHY??) 8. Steps 3 to 7 were repeated for another 6 different pressures that could be as close as possible too 5, 100, 500, 1600, 3900 and 8100 Pa. Heat Transfer by Radiation | Input Power setting = 56% (% maximum power) | Input power = 9 (Watts) | Reading No. | Air Pressure (Absolute) (kPa) | Air Pressure Raised to Power of 0.25 (kPa) | Copper Rod Temperature T1 (°C) | Surroundings Temperature T2 (°C) | 1 | 5 | 1.495348 | 179 | 25.6 | 2 | 101 | 3.170153 | 173.2 | 25.9 | 3 | 455.5 | 4.619788 | 170.3 | 26.1 | 4 | 1530 | 6.254215 | 168.3 | 26.3 | 5 | 3770 | 7.835835 | 166.7 | 26.4 | 6 | 7700 | 9.367477 | 164.4 | 26.5 |

Graph 1 below shows the linear relationship between temperatures of both the heated copper rod and the surrounding vessel wall versus the air pressure raised to the power of 0.25 together with extrapolated values of the temperature.

1.1. Assumptions

* Steady state operating conditions exist at the time of readings taken. * The copper rod is completely surrounded by the walls of the pressure vessel. * Heat transfer by convection is not considered. * Heat transfer by conduction through the copper rod’s suspending medium is negligible.
Calculations

The
Show More

Related Documents: Essay on Design of Machine Elements

Computer Integrated Manufacturing

Detailed Outline – Page 1 Unit 1: Principles of Manufacturing Time Days: 32 days Lesson 1.1: History of Manufacturing (8 days) Concepts Addressed in Lesson 1. Manufacturing is a series of interrelated activities and operations that involve product design, planning, producing, materials control, quality assurance, management, and marketing of that product. 2. Manufacturing is essential to a healthy economy, including jobs and attainment of personal goals. 3. National manufacturing avoids health risks…

Words 1914 - Pages 8

America In The Gilded Age

The political elements of America in the Gilded Age had an active impact on the power distribution throughout American cities. During this time, there were organizations that craved power known as political machines. These political machines became very dominant in almost all large American cities due to favorable relationships with real estate and businesses, as well as by mobilizing large blocs of immigrant and working-class voters (Keene, 508). There were many contributors to the rise of political…

Words 466 - Pages 2

Essay on ENG 225 Week 2 Elements of Design

This work contains ENG 225 Week 2 Elements of Design Elements of Design. During the process of envisioning and designing a film, the director, production designer, and art director (in collaboration with the cinematographer) are concerned with several major spatial and temporal elements. These design elements punctuate and underscore the movement of figures within the frame, including the following: setting, lighting, costuming, makeup, and hairstyles. Choose a scene from movicclips…

Words 360 - Pages 2

Essay Mgt 3305 Exam 2 Study Guide Spring 2015

costs of project, and activity completion times It is often referred to as “crashing” the project to reduce overall duration. Chapter 9 Characteristic that can be used to guide the design of service systems service triangle factors that distinguishes service design and development from manufacturing design and development 1. The process and the product must be developed simultaneously. The process is the product. 2. A service operation lacks the legal protection commonly available to products…

Words 689 - Pages 3

Chapter 7 Job Design Essay

Chapter 7: Design of Work Systems Answers to Discussion and Review Questions 1. Job design is concerned with specifying the contents and methods of jobs. It is important because it has a significant impact on the efficiency and productivity of workers. 2. From the standpoint of management, having workers with specialized skills can substantially lower the total cost of a product and also requires less training. The disadvantages for management include the following: a) Workers may be somewhat…

Words 2096 - Pages 9

Bunn Research Paper

method of drip operation, Bunn entered the home consumer market with a different type of automatic drip-brew machine. In this type of coffeemaker, the machine uses a holding tank or boiler pre-filled with water. When the machine is turned on, all of the water in the holding tank brought to near boiling point (approximately 200-207 F or 93-97 C) using a thermostatically-controlled heating element. When water is poured into a top-mounted tray, it descends into a funnel and tube which delivers the cold…

Words 438 - Pages 2

The Concept Of Fotation Machine

Normally, the improvement on the new flotation machine follows the geometric similarity from the structural elements, the related concepts of your fluid dynamics of liquid flow construction and the train of imagined to be sure the investment plus the manufacturing expenses with the large-volume flotation machine thoughts. The large-volume flotation machine drew substantially attention through the 1990s. Thus far, the volume with the flotation cell has expanded to 300m³ to 500m³. However, in many…

Words 388 - Pages 2

Cone crusher is the best equipment for processing pebble Essay

Pebble is a kind of natural stone material,it is widely distributed in various channel, after thousands of years of water erosion,rock pulveriser manufacturer in indiapebble itself contains a large element of silicon, which caused the cobble hardness is very big, so in the process of broken pebble, what we should use is the high wear resistance equipment, and cone crusher is the optimal choice of cobble crushing equipment. Compared with other rock crusher, the cone crusher is easy to adjust and…

Words 432 - Pages 2

Nt1330 Unit 1 Exercise 1.2.1 Study

critical to VMware:  Virtual Machine  Guest OS  Host OS. Most central is the “virtual machine.” A virtual machine is a way of representing a real machine using software to control the implementation of an operating system. The operating system that is being…

Words 687 - Pages 3

Digital electronics Essay

electronic circuits are usually made from large assemblies of logic gates, simple electronic representations of Boolean logic functions.[1] Contents [hide] 1 Advantages 2 Disadvantages 3 Design issues in digital circuits 4 Construction 4.1 Structure of digital systems 4.2 Automated design tools 4.3 Design for testability 4.4 Trade-offs 4.4.1 Cost 4.4.2 Reliability 4.4.3 Fanout 4.4.4 Speed 4.5 Logic families 5 Recent developments 6 See also 7 References 8 External links Advantages[edit]…

Words 4452 - Pages 18