Partial Thermo analysis of a Crower engine

In summary, the author is trying to calculate what happens during the water injection process in a six cycle engine. On an intuitive level, they think that the injected water heats the air to its boiling point, and reduces the pressure accordingly. The hot air then vaporizes the liquid water, causing two things to happen: the air is further cooled by the water's heat of vaporization, and the newly formed steam expands greatly. There is always assumptions made because the author is trying to simplify the problem, but they think that the amount of liquid water injected is small and the air displaced by the water is small enough to ignore any pressure increase. They are currently able to calculate steps 1 and 2, but Step 3 has them stumped
  • #1
Larry27183
3
0
Hi everyone. Some years ago I read about the Crower six cycle engine. Always wanted to understand it better. And now is the time to follow up on that desire.

I’m trying to calculate what happens during the water injection. The goal is to determine the conditions (pressure, temperature) after water injection and before the second expansion / power stroke.

On an intuitive level here’s what I think is happening:
1) The hot air heats the injected water to its boiling point. (above 100C, as determined by the cylinder pressure.)
2) Heating the water cools the air, and reduces the pressure accordingly.
3) The hot air then vaporizes the liquid water, causing two things to happen:
o The air is further cooled by the water’s heat of vaporization (which also reduces the cylinder pressure), and
o The newly formed steam expands greatly, causing the pressure and temperature to increase.

There’s always assumptions. Here are mine:
* To keep things simple, the cylinder starts with hot compressed air instead of combustion exhaust (CO2, steam, and who knows what else). Perhaps I’ll revisit this later.
* The amount of liquid water injected is small. The air displaced by the water is small enough to ignore any pressure increase.

Currently I can calculate steps #1 and #2, but Step #3 has me stumped and befuddled. Perhaps you can walk me through how to get the resulting conditions. Links to previously worked out problems would be great also.

Thanks for your help!
 
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  • #2
:welcome:

You'll get better answers if you provide us a link to what you have been reading. Wikipedia does not have anything about the Crower engine.
 
  • #3
Wikipedia's article on six stroke engines is here:
https://en.wikipedia.org/wiki/Six-stroke_engine

An interesting introduction to Bruce Crower and his engine:
https://autoweek.com/article/car-news/inside-bruce-crowers-six-stroke-engine
https://autoweek.com/article/car-news/inside-bruce-crowers-six-stroke-engine
A google search for "six stroke engine" (or "six-stroke engine") turns up many hits. Scholarly papers are available that analyze the engine but I have not found one that shows how the water vaporization process is calculated.

Thanks!
 
  • #4
You should need to understand two concepts.

First, because there are two gases (air and steam), you need to use the partial pressure concept (Dalton's law).

Second, for the steam, you need to use the steam tables. There is a simple introduction here. Knowing two of the steam properties, you should find all others.

I haven't used these for a long time, so I'm kind of rusty on how to apply it to your problem, but I'm pretty sure this is the way to go. Conservation of enthalpy might be helpful for steam properties.
 
  • #5
Jack,

Thanks for the feedback. I was thinking along similar lines but hoping there was a simpler way. I'll look into it as time allows.

Please excuse the delay in responding. Life threw me a curve ball and gave me a completely unexpected job interview. I got the job today!
 
  • #6
Larry27183 said:
I got the job today!
Congratulations! :partytime:
 

Related to Partial Thermo analysis of a Crower engine

1. What is partial thermo analysis?

Partial thermo analysis is a scientific method used to analyze the thermal performance of an engine by measuring its temperature and heat transfer characteristics at specific points.

2. How does partial thermo analysis work?

Partial thermo analysis involves attaching thermocouples and heat flux sensors to specific points on the engine and collecting data on temperature and heat transfer. This data is then used to calculate important parameters such as heat transfer coefficients and thermal efficiencies.

3. Why is partial thermo analysis important for Crower engines?

Partial thermo analysis allows for a detailed understanding of the thermal behavior of Crower engines, which can help engineers optimize their design and improve performance. It can also help identify potential issues or areas for improvement in the engine.

4. How is partial thermo analysis different from other types of engine analysis?

Partial thermo analysis focuses specifically on the thermal behavior of an engine, while other types of analysis may also consider factors such as mechanical performance or emissions. Additionally, partial thermo analysis involves measuring temperature and heat transfer at specific points, rather than overall performance measures.

5. What are some potential applications of partial thermo analysis for Crower engines?

Partial thermo analysis can be used for various purposes, such as evaluating the performance of new engine designs, troubleshooting issues with an existing engine, or comparing the performance of different engine components. It can also help in the development of more efficient and reliable Crower engines.

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