Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Lenoir Cycle shopping experience:
1. Compare - without doubt the biggest advantage that the Lenoir Cycle offers shoppers today is the ability to compare thousands of Lenoir Cycle at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.
2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about
3. Testimonials - don't know anybody that has bought a Lenoir Cycle? Wrong! If the Lenoir Cycle is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.
4. Questions - Got a question about Lenoir Cycle then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....
5. Reputation - Never heard of the company selling Lenoir Cycle? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Lenoir Cycle and build up a picture of their reputation for sales, returns, customer service, delivery etc.
6. Returns - still worried that even after all of the above your Lenoir Cycle wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.
7. Feedback - happy with your Lenoir Cycle then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.
8. Security - check for the yellow padlock on the Lenoir Cycle site before you buy, and the s after http:/ /i.e. https:// = a secure site
9. Contact - got a question about Lenoir Cycle, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.
10. Payment - ready to pay for your Lenoir Cycle, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.
The
Lenoir cycle is an idealised thermodynamic cycle often utilized to model a
pulse jet engine. It is based on the operation of an engine patented by Jean Joseph Etienne Lenoir in 1860. This engine is often thought of as the first commercially produced internal combustion engine. The absence of any compression process in the design leads to lower thermal efficiencies than the more well known
Otto cycle and
Diesel cycle.
In the cycle, an ideal gas undergoes
1-2: Constant volume (isochoric) heat addition
2-3: Isentropic process expansion.
3-1: Constant pressure (isobaric process) heat rejection - compression to the volume at the start of the cycle.
The expansion process is isentropic process and hence involves no heat interaction. Energy is absorbed as heat during the constant volume process and rejected as heat during the constant pressure process.
Constant volume heat addition (1-2)
In the ideal gas version of the traditional Lenoir cycle, the first stage (1-2) involves the addition of heat in a constant volume manner. This results in the following for the first law of thermodynamics:{}_1Q_2 = mc_v \left( {T_2 - T_1 } \right)
There is no work during the process because the volume is held constant:{}_1W_2 = \int\limits_1^2 {pdV} = 0
and from the definition of constant volume specific heats for an ideal gas:c_v = \frac{R}
Where
R is the ideal gas constant and
γ is the ratio of specific heats (approximately 287 J/(kg·K) and 1.4 for air respectively). The pressure after the heat addition can be calculated from the ideal gas law: p_2 V_2 = RT_2
Isentropic expansion (2-3)
The second stage (2-3) involves a reversible adiabatic expansion of the fluid back to its original pressure. It can be determined for an isentropic process that the second law of thermodynamics results in the following:\frac = \left( {\frac} \right)^{{\textstyle{{\gamma - 1} \over \gamma -->} = \left( {\frac} \right)^{\gamma - 1}
Where p_3 = p_1 for this specific cycle. The first law of thermodynamics results in the following for this expansion process: {}_2W_3 = mc_v \left( {T_2 - T_3 } \right) because for an adiabatic process:{}_2 Q_3 = 0
Constant pressure heat rejection (3-1)
The final stage (3-1) involves a constant pressure heat rejection back to the original state. From the first law of thermodynamics we find: {}_3Q_1 - _3 W_1 = U_1 - U_3 .
From the definition of work: {}_3W_1 = \int\limits_3^1 {pdV} = p_1 \left( {V_1 - V_3 } \right), we recover the following for the heat rejected during this process: {}_3Q_1 = \left( {U_1 + p_1 V_1 } \right) - \left( {U_3 + p_3 V_3 } \right) = H_1 - H_3 .
As a result, we can determine the heat rejected as follows: {}_3Q_1 = mc_p \left( {T_1 - T_3 } \right)from the definition of constant pressure specific heats for an ideal gas: c_p = \frac.
The overall efficiency of the cycle is determined by the total work over the heat input, which for a Lenoir cycle equals: \eta _{th} = \frac{{{}_2W_3 + {}_3W_1 -->{{{}_1Q_2 -->. Note that we gain work during the expansion process but lose some during the heat rejection process.
Cycle diagrams
External links
- Thermodynamic cycle simulation program including an option for Lenoir cycle
The
Lenoir cycle is an idealised thermodynamic cycle often utilized to model a
pulse jet engine. It is based on the operation of an engine patented by
Jean Joseph Etienne Lenoir in 1860. This engine is often thought of as the first commercially produced internal combustion engine. The absence of any compression process in the design leads to lower thermal efficiencies than the more well known
Otto cycle and
Diesel cycle.
In the cycle, an
ideal gas undergoes
1-2: Constant volume (
isochoric) heat addition
2-3: Isentropic process expansion.
3-1: Constant pressure (isobaric process) heat rejection - compression to the volume at the start of the cycle.
The expansion process is isentropic process and hence involves no heat interaction. Energy is absorbed as heat during the constant volume process and rejected as heat during the constant pressure process.
Constant volume heat addition (1-2)
In the ideal gas version of the traditional Lenoir cycle, the first stage (1-2) involves the addition of heat in a constant volume manner. This results in the following for the first law of thermodynamics:{}_1Q_2 = mc_v \left( {T_2 - T_1 } \right)
There is no work during the process because the volume is held constant:{}_1W_2 = \int\limits_1^2 {pdV} = 0
and from the definition of constant volume specific heats for an ideal gas:c_v = \frac{R}
Where
R is the ideal gas constant and
γ is the ratio of specific heats (approximately 287 J/(kg·K) and 1.4 for air respectively). The pressure after the heat addition can be calculated from the ideal gas law: p_2 V_2 = RT_2
Isentropic expansion (2-3)
The second stage (2-3) involves a reversible adiabatic expansion of the fluid back to its original pressure. It can be determined for an isentropic process that the second law of thermodynamics results in the following:\frac = \left( {\frac} \right)^{{\textstyle{{\gamma - 1} \over \gamma -->} = \left( {\frac} \right)^{\gamma - 1}
Where p_3 = p_1 for this specific cycle. The first law of thermodynamics results in the following for this expansion process: {}_2W_3 = mc_v \left( {T_2 - T_3 } \right) because for an adiabatic process:{}_2 Q_3 = 0
Constant pressure heat rejection (3-1)
The final stage (3-1) involves a constant pressure heat rejection back to the original state. From the first law of thermodynamics we find: {}_3Q_1 - _3 W_1 = U_1 - U_3 .
From the definition of work: {}_3W_1 = \int\limits_3^1 {pdV} = p_1 \left( {V_1 - V_3 } \right), we recover the following for the heat rejected during this process: {}_3Q_1 = \left( {U_1 + p_1 V_1 } \right) - \left( {U_3 + p_3 V_3 } \right) = H_1 - H_3 .
As a result, we can determine the heat rejected as follows: {}_3Q_1 = mc_p \left( {T_1 - T_3 } \right)from the definition of constant pressure specific heats for an ideal gas: c_p = \frac.
The overall efficiency of the cycle is determined by the total work over the heat input, which for a Lenoir cycle equals: \eta _{th} = \frac{{{}_2W_3 + {}_3W_1 -->{{{}_1Q_2 -->. Note that we gain work during the expansion process but lose some during the heat rejection process.
Cycle diagrams
External links
- Thermodynamic cycle simulation program including an option for Lenoir cycle
Lenoir cycle - Wikipedia, the free encyclopedia
The Lenoir cycle is an idealised thermodynamic cycle often utilized to model a pulse jet engine. It is based on the operation of an engine patented by Jean Joseph Etienne Lenoir in ...
Étienne Lenoir - Wikipedia, the free encyclopedia
The Motoring Pioneer" in Ward, Ian, executive editor. The World of Automobiles, p.1181-2. London: Orbis Publishing, 1974. [edit] See also. Lenoir cycle
lenoir_freecycle : Lenoir, NC Freecycle
lenoir_freecycle: Lenoir, NC Freecycle ... The Lenoir Freecycle™ group is for all who want to find a new home for reuseable items.
lenoirfreecycle : Lenoir County Freecycle™ Network
lenoirfreecycle: Lenoir County Freecycle™ Network ... Welcome to Lenoir County's Freecycle™ Network. This network is open to residents of Lenoir County and its surrounding area ...
The Freecycle Network - about the Lenoir County Group
Welcome to the Lenoir County Freecycle group! The Freecycle Network™ is made up of 4,566 groups with 5,605,385 members across the globe. It's a grassroots and entirely nonprofit ...
The Freecycle Network - about the Lenoir (Caldwell Co) Group
Welcome to the Lenoir (Caldwell Co) Freecycle group! The Freecycle Network™ is made up of 4,566 groups with 5,651,795 members across the globe.
Lenoir City - Hutchinson encyclopedia article about Lenoir City
City in eastern Tennessee, on the Tennessee River, 37 km/23 mi southwest of ... Lenoir cycle Lenoir Jean-Joseph-Etienne Lenoir rhyne Lenoir Rhyne College Lenoir, (Jean Joseph ...
Lenoir - Hutchinson encyclopedia article about Lenoir
City and administrative headquarters of Caldwell County, western North Carolina, in ... Lenoir cycle Lenoir Jean-Joseph-Etienne Lenoir rhyne Lenoir Rhyne College Lenoir, (Jean Joseph ...
Lenoir definition of Lenoir in the Free Online Encyclopedia.
Lenoir (lənôr`), city (1990 pop. 14,192), seat of Caldwell co., W N.C.; inc. 1851. ... Lenoir cycle Lenoir Jean-Joseph-Etienne Lenoir rhyne Lenoir Rhyne College Lenoir, (Jean Joseph ...
Lenoir City Utility Board - What does LCUB stand for? Acronyms and ...
Acronym Definition; LCUB: Lenoir City Utility Board? ... Lenoir cycle Lenoir Jean-Joseph-Etienne Lenoir rhyne Lenoir Rhyne College Lenoir, (Jean Joseph ...
