Tesla Turbine For Household Usage As Green Energy Engineering Essay

Published:

This essay has been submitted by a student. This is not an example of the work written by our professional essay writers.

This project is to develop a Tesla turbine for household usage as green energy with the objective to generate electricity using household water supply without significant head loss. In this project, the development will be carried out in 4 stages. The 1st stage is the theoretical calculation of Tesla Turbine certain parameters, such as disc size, disk gap, number of disc. The purpose of the theoretical calculation is to use the calculated theoretical value as a guideline to start the process of optimization using computational fluid dynamic (CFD). 2nd stage is the optimization process. The optimization process is conducted using EFD software. After the design of the Tesla turbine is optimized, the 3rd stage can proceed to fabricate the Tesla Turbine. The Tesla turbine will

be mainly made of acrylic and aluminium. When the prototype of the Tesla turbine is ready, performance analysis will be conducted. Analysis is focused on the RPM and torque generated by the Tesla Turbine. At current stage it is found that the initial design of Tesla turbine able to generate 0.021N.m torque with the head loss of 0.44 m

Keywords

Tesla turbine; Bladeless turbine; Viscous turbine; CFD; COSMO FloWorks2008.

1. Introduction

This project is to develop a Tesla turbine for household usage as green energy with the objective to generate electricity using household water supply without significant head loss. Through the data provided from the Jabatan Kerja Raya(JKR), the residential area at Perlis has an average 10.3m residual head for a single storey building, which is ample to supply water to a single storey water tank. [1] Thus, the purpose of this project is to use Tesla Turbine to convert the excessive energy to usable electrical energy without affecting the supply of water to the single storey water tank.

1.1 Background

The Tesla Turbine is invented by Nikola Tesla in 1913.It is known for its bladeless centripetal flow turbine. [2, 3, 19,20] Tesla Turbine consisted of an array of parallel thin disks very close to each other, kept apart by spacers and assembled on a shaft, forming a rotor which was fitted in a cylindrical housing its ends closed by plates properly fitted with bearings to hold the rotor shaft. In the central region of the disks, close to the shaft, exhaust ports were opened, with gaps in the spacers, thus providing an exit to the atmosphere. A nozzle was located tangentially to the bore of the casing, feeding the working fluid, onto the disks, rotating them while proceeding to the exhaust ports.[4]

Figure 1.1 - Flow Trajectories in the Tesla Turbine

As show in figure 1.1, Tesla turbine has a number of closely-spaced flat disks mounted on a shaft, driven by a fluid flowing between them, in spirals concentric with the shaft, toward a center outlet.  The energy transfer does not occur through impingement.  Instead, the fluid's energy is imparted to the disks through the force of adhesion.  When the fluid makes contact with a disk its molecules adhere to the disk and resist departure.  The force of the fluid works against the resistance of the disk and some of the fluid's energy imparts to the disk.  The force of viscosity, or adhesion between layers of fluid molecules, enables more fluid to act on the disk than is able to adhere to it.  The layer of fluid which is able to act on the disk through viscosity is called the boundary layer.  As the fluid loses energy it is drawn out by the lower pressure in the turbine outlet. [5]

1.2 Objective

To fabricate a Tesla turbine

A prototype Tesla turbine is needed so for that an experimental analysis can be conducted. Fabrication on Tesla turbine is for a better understanding on the working principle of Tesla turbine. Through process fabrication, good feature and bad feature are able to identify for further improvement.

To analyze the performance of Tesla turbine.

Performance of the Tesla turbine is analyzed so that experimental result can be compare with EFD analysis result. If both result vary at a large degree, further analysis is needed t identify the root cause. Besides, by analyzing the performance of Tesla turbine good features are able to strengthen and bad feature are able to eliminate.

To evaluate the best design among the studied parameters for Tesla Turbine with the low inlet pressure working environment.

This Tesla Turbine is specially built for low inlet working environment. Thus, specific designs of parameters are needed to be optimized, in order for the Tesla turbine to function efficiently.

1.3 Scope

In any design process, all design factors and parameters have to be considered and optimized, in order to achieve the best performance of a product. The scopes of this project are as the following:

Working fluid: Pipe water.

The working fluid of this project is the pipe water which supply to the resident of Perlis where having, , . Outlet water from Tesla turbine should at least reach the reservoir tank of single storey building in Perlis residential area

Studied parameters:

Gap between discs

Tesla turbine design has the fluid flow between two parallel disks in which the gap is small enough to limit the flow to boundary layer conditions. If the flow rate is limited, the result is laminar flow. The energy transfer takes place by the shear forces between fluid and rotor.

Disk Size

A larger diameter provides increased shaft torque and is limited by centrifugal stress, while smaller diameter provides increased shaft speed and is limited by bearing friction

Number of disk

The flow rate for a single disk gap can be calculated using the equation and that data used to determine how many disks are required for a given flow through the pump or turbine.

1.4 Problem Statement

Table 1.1 Energy Mix in Malaysia

Petroleum, natural gas, and coal is the main power source of Malaysia, it generates about 90 percent of our power supply. These hydrocarbon resources are not renewable energies which will one day depleted. [6]

Besides, using conventional non-renewable energy such as fossil fuels (oil and coal) and natural gas in the energy mix has two major disadvantages. The nature of non-renewable energy causing it to extinct and secondly, the combustion of non-renewable energy like oil, coal and natural gas is a major contribution to the emission of greenhouse gasses that raise the issue of climate change. Both of these issues are of major global environmental concerns that will have disastrous impact on the socio-economic development in Malaysia. [6]

Thus, it is crucial to utilize any available resources to convert into usable energy without polluting the nature.

2. Literature Review

2.1 Basic Design of Tesla Turbine

Figure 2.1 2D View of Tesla Turbine

The Tesla turbine is a rotor consists of flat parallel co rotating disks spaced along a shaft [2, 7, 8, 19]. Fluid flows through the gap between disk results in momentum exchange between the fluid and disks and hence shaft torque and power. In other words, the fluid drags on the disk by means of viscosity and the adhesion of the surface layer of the gas. As the gas slows and adds energy to the disks, it spirals in to the center exhaust. Since the rotor has no projections, it is very sturdy. [2, 7, 8, 9].

2.2 Purpose of the Project

Tesla turbine can be one of the alternative renewable energy which is affordable and free pollution. From Strategies for Promotion and Development of Malaysia Renewable Energy written by K.S.Kannan [10] claim that the potential use of renewable energy in Malaysia is important: only 4% of the hydropower is tapped today. For solar energy, the market for domestic solar water heaters in only emerging and stand-alone photovoltaic system could be cost-effective for rural electrification in remote.

Besides, in an article "Rebirth of Tesla Turbine" said that the three main sources of air pollution are: internal combustion engines, coal-fired power plants, and the manufacturing sector. The only viable technology capable of delivering the elusive sustainable growth formula - more power, less pollution, lower cost - is the Tesla or boundary layer turbine [11].

2.3 Capability of Tesla Turbine

An analytical result conduct by Warren Rice: "Tesla Turbomachinery"; Proc. IV International Nikola Tesla Symposium (Sept. 23-25, 1991), claimed that the rotor efficiency using laminar flow can be very high, even above 95%. [11] However, in order to attain high rotor efficiency, the flow rate number must be made small which means high rotor efficiency is achieved at the expense of using a large number of disks and hence a physically large rotor [9].

Experiments with prototype turbines published in peer-review journals indicate a somewhat linear relationship between turbine efficiency and rotor rpm.  At fixed pressures and varying loads, Singleton [12] reported 21% at 5k rpm, 24% at 7k rpm and 28% at 9k rpm.  Schmidt [13] reported (Beans 1966) 24% at 12k rpm and (Gruber 1960) 32% at 15k rpm (also simulated by Huybrechts). Rice (1965) [9] reported 22.5% at 8k rpm, 24.5% at 10k rpm and 26.5% at 12k rpm. 

2.4 Energy Grade Line (EGL)

It is often convenient to represent the level of mechanical energy graphically using heights to facilitate visualization of the various terms of the Bernoulli equation. [14] This is done by dividing each term of the Bernoulli equation by g to give

(1)

Characteristic of EGL on turbine and pump:

A steep jump occurs in EGL and HGL whenever mechanical energy is added to the fluid (by a pump, for example). Likewise, a steep drop occurs in EGL and HGL whenever mechanical energy is removed from the fluid (by a turbine, for example), as shown in figure 2.2

Figure 2.2 Energy Grade Line (EGL) and Hydraulic Grade Line (HGL)

2.5 Turbine Efficiency

By convention, turbine efficiency is based on net head, H rather that gross head Hgross. [14] Specifically, ηturbine is defined as the ratio of brake horsepower output (actual turbine output shaft power) to water horsepower (power extracted from the water flowing through the turbine),

(2)

2.6 Disk Gap

According to a paper by Glenn A. Barlis, "The disk gap is a critical parameter in the design. The analysis by Brieter and Pohlhausen shows that the optimum gap size to maintain the boundary layer is

(3)

(4)

The Polhausen parameter has an important influence on the performance, because it determines to what extent the bulk fluid follows the rotation of the disc, and it controls the shape of the disk-to-disc velocity distribution.[10, 16, 17]

Too small Ph values approach the case of the solid body rotation, while too large values correspond to almost decoupled boundary layer on the two discs and a non-rotating core in-between. For this reason, in friction pumps the Polhausen parameter is usually kept within narrow limit,

2.7 Number of Disc

Hasinger and Kehrt provide a dimensionless parameter that has essential machine data. Using the above empirical formula, the number of disks is able to estimate. [10, 16, 18]

(5)

(6)

After doing some algebra, the following equation is formed

(7)

The various analyses show that the flow rate between the disks must be kept relatively low for good efficiency. Logically enough, this says that you have to increase the number of disks in proportion to the flow rate.

Thus,

(8)

3. Methodology

This chapter explains the design, simulation, and optimization.

3.1 Flow chart of the project

Figure 3.1 Flow chart of project

3.2 Conceptual Design

The following CAD model is developed by using Solidworks:

3D Modeling:

Figure 3.2 Conceptual Design of Tesla Turbine

Explode View:

Figure 3.3 Explode View of Tesla Turbine

3.3 Initial Parameter and Boundary Condition

Initially, the inlet flow rate of the residential area in Perlis has to be determined. A simple experiment is done to determine the inlet flow rate. It found that the inlet flow rate of the residential area varies accordingly to the distance between the reservoir and the house where the measurement is taken. The lowest flow rate 0.32kg/s is chosen to be the inlet flow rate for the simulation, because if a Tesla turbine is design for a high flow rate, the rotor might not even rotate due to the exceeding number of disc.

The following Table 4.1 is the inlet flow rate of residential area in Perlis. The experiment is conducted in 3 single storey houses at Taman Semarak 2.

Table 3.1 Inlet flow rate of residential area in Perlis

 

Mass Flow Rate

Count

Location 1

Location 2

Location 3

1

0.33

0.40

0.49

2

0.32

0.41

0.48

3

0.33

0.39

0.47

4

0.33

0.40

0.47

5

0.33

0.40

0.48

6

0.32

0.40

0.48

7

0.33

0.39

0.49

8

0.32

0.40

0.48

9

0.33

0.39

0.46

10

0.32

0.39

0.48

Average

0.32

0.40

0.48

3.4 Estimation of Design Parameter

By using the empirical formula, the disc gap and the number of disk can be estimated.

Disk Gap

Data in Table 4.2 is the estimation of disk gap. The 1000 RPM is applied in the empirical formula because most low RPM generator or alternator generates powers at around 100 to 600 rpm.[15]

Table 3.2 Estimation of Disc Gap

RPM

1000

104.7198

Ph

b,m

b,mm

2.5

0.000244

0.244301

2.6

0.000254

0.254073

2.7

0.000264

0.263845

2.8

0.000274

0.273617

2.9

0.000283

0.283389

3

0.000293

0.293162

3.1

0.000303

0.302934

3.2

0.000313

0.312706

3.3

0.000322

0.322478

3.4

0.000332

0.33225

3.5

0.000342

0.342022

Number of Disc

The number of disc in table 4.3 is determined by using Hasinger and Kehrt provided dimensionless parameter. According to Nikola Tesla, the torque of the Tesla Turbine is directly proportional to the number of disc. Thus, the highest number of disk is chosen as the design parameter for the simulation.

Table 3.3 Number of Disc

A

q

n

10

0.015613

20

11

0.017174

19

12

0.018735

17

13

0.020297

16

14

0.021858

15

15

0.023419

14

16

0.024981

13

17

0.026542

12

18

0.028103

11

19

0.029665

11

20

0.031226

10

158

Number of Disk

14

4. Project Progress

Initial simulation is done on the initial design of Tesla turbine. Table 4.1 and figure 4.1 are the simulation result obtained from CFD analysis.

Table 4.1 Torque of Tesla Turbine

Goal

Unit

Value

Torque

[N*m]

0.021054786

Figure 4.1 Graph of Torque VS Iteration

Table 4.1 shows the final torque of the iteration. The final iteration means that the torque of the Tesla Turbine had converged and reaches to equilibrium.

By observing figure 4.1, it is able to noticed that the iteration converged when the torque reaches 0.021054786 N.m. This concluded that the initial design of Tesla Turbine can only yield 0.021N.m.

Figure 4.2, shows the flow trajectories of the Tesla turbine. From the flow trajectory, it is observed that the streamline of the fluid circles around the disc and directed to the outlet. As the particle of fluid moving towards, it will result a momentum change between the fluid and the disc hence shaft torque and power

Figure 4.2 Flow Trajectories in Tesla Turbine

4.1 Efficiency of Tesla Turbine

Table 4.2 show the static pressure and velocity for both inlet and outlet of Tesla Turbine.

Table 4.2 Pressure and Velocity of Inlet and Outlet

Goal Name

Unit

Value

Inlet Pressure, P1

[Pa]

103896.0769

Outlet Pressure,P2

[Pa]

101325.0062

Inlet Velocity,V1

[m/s]

4.19738696

Outlet Velocity,V2

[m/s]

0.68030031

Using the obtained the torque, the efficiency of the Tesla Turbine can be estimated

6.8%

Through the calculation, it is found that the efficiency of the Tesla Turbine at 1000 RPM will have an efficiency of 6.8%.

4.2 Head Loss of Tesla Turbine

By using Bernoulli equation and energy grade line (EGL), the head loss cause by the Tesla Turbine can be found.

From the calculation, the head loss resulted by the Tesla Turbine is 0.44m.

5. Conclusion

In current stage, it is notice that a Tesla Turbine with diameter of 110mm and 21 disks will generate a torque of 0.021N.m. Besides, it will have an efficiency of 6.8% which fairly low compare to the results from other journals and research. This is probably due to the limitation of low inlet flow rate. Besides, this Tesla Turbine will result a head loss of 0.44mm which is still within the acceptable range.

On the next plan, optimization process will proceed. Parameter such as disc size, disk gap, and number of disc will be optimized. The purpose of the optimization is to obtain the best design parameter for Tesla turbine to work under low inlet water pressure.

Writing Services

Essay Writing
Service

Find out how the very best essay writing service can help you accomplish more and achieve higher marks today.

Assignment Writing Service

From complicated assignments to tricky tasks, our experts can tackle virtually any question thrown at them.

Dissertation Writing Service

A dissertation (also known as a thesis or research project) is probably the most important piece of work for any student! From full dissertations to individual chapters, we’re on hand to support you.

Coursework Writing Service

Our expert qualified writers can help you get your coursework right first time, every time.

Dissertation Proposal Service

The first step to completing a dissertation is to create a proposal that talks about what you wish to do. Our experts can design suitable methodologies - perfect to help you get started with a dissertation.

Report Writing
Service

Reports for any audience. Perfectly structured, professionally written, and tailored to suit your exact requirements.

Essay Skeleton Answer Service

If you’re just looking for some help to get started on an essay, our outline service provides you with a perfect essay plan.

Marking & Proofreading Service

Not sure if your work is hitting the mark? Struggling to get feedback from your lecturer? Our premium marking service was created just for you - get the feedback you deserve now.

Exam Revision
Service

Exams can be one of the most stressful experiences you’ll ever have! Revision is key, and we’re here to help. With custom created revision notes and exam answers, you’ll never feel underprepared again.