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脉动式喷气发动机计算器

2017-11-15 21:06| 发布者: dymodel| 查看: 381| 评论: 0|原作者: sirius

摘要: Note from the Editor: Eric's Pulsejet Calculator is probably one of the most useful tools ever offered to the amateur experimenter. It allows quick and easy calculation of all critical dimensions, ...
Note from the Editor:
Eric's Pulsejet Calculator is probably one of the most useful tools ever offered to the amateur experimenter. It allows quick and easy calculation of all critical dimensions, including the  cutting patterns for cone sheets. We are proud to offer Eric's complete description and instructions for use of the program, as well as our own link for downloading your copy, at no cost. The program is actually an XLS [Excel spreadsheet] file, so you'll need MS ExcelTM installed to use it.
Here's what is unique about Eric's program: Several pulsejet design programs have been developed based on theory - they usually only work acceptably for engines of fairly large size.
Eric's spreadsheet formulae are based not on strict theory, but rather on his own observations of the design of successfully tested valved pulsejets that have been developed over the years in a wide variety of sizes and three distinct valve designs. His method tends to produce tailpipe designs that are reasonably proportioned and buildable for all practical sizes of valved engines [as Eric mentions in his article, there are some special considerations that need to be understood in getting extremely small pulsejets to work].
While we believe that operation of the program is correct, and that it should consistently yield satisfactory results, the author takes complete and sole responsibility for support of this program.
We hope you'll enjoy using this unique design tool!
- Larry Cottrill, Editor
_____________________________________________________
Introduction
A pulsejet engine is one of the most fascinating types of engines I have ever encountered. The pulsejet is mechanically very simple, but the physics behind how a pulsejet works is intriguingly complex. Pulsejets can be used to power a variety of different types of vehicles ranging from planes to go-karts.
Because pulsejets are so simple to make compared to gas turbines,amateurs and hobbyists often choose to build them when they want jet power. This is where people can run into problems. Although just copying a proven design is easy, designing and building your own pulsejet engine can be extremely difficult if you do not know where to start. Often people can be discouraged by a poor engine design and decide to quit working on it altogether.
Over the past several years, I have been studying pulsejet engines in detail. I have designed and built several engines and many things to improve their performance. I have studied every aspect about every working pulsejet design I have found. I have also read much literature about the history of this type of engine, and about previous studies of the pulsejet engine. I wassearching to find some type of law or equation that governed a pulsejet engine's dimensions. With the data I gathered, I hoped to one day make a program that would help people be able to design their own valved pulsejet engine.   
Shortly after writing my book on pulsejet engines (which I hope to release soon), How to Design and Build an Advanced Pulsejet Engine, I decided to sum up many of the equations into one excel program so that the dimensions for any size pulsejet engine could be calculated almost instantly.
I decided to have the program focus on the design of the tailpipe of the engine. The tailpipe design is crucial to the operation of the engine and is so commonly out of proportion in the average home-designed engines. The dimensions generated by this program are extremely accurate and have very high correlation with well-designed real world engines. By simply entering the thrust you want the engine to produce, every aspect of the tailpipe dimensions are generated. The estimated frequencythat the engine will operate is also on this page. In the next version I hope to add a page to calculate all other dimensions such as fuel system, valve head, and the valves.
What people must understand is while the dimensions generated for a very small pulsejet (under 2 pounds thrust) are accurate to theoretical values, they still may not run with ease. The smaller a pulsejet engine is, the more precise every aspect of the pulsejet engine's construction and operation must be. It is also difficult to get fuel to mix properly in a small engine, and variations in atmospheric pressure and temperature will have more of an effect on a smaller engine. These are all things that cause small engines to be difficult to run. A small engine is not recommended for a beginner’s first engine.
Early versions of my program only calculated the basic dimensions of the engine. My new release Pulsejet Calculator V1.4 is a major improvement over previous versions. Each part of the program is on a different page, all contained in one Excel spreadsheet. Before going into how to use the program in detail, I will briefly summarize the basic functions of the program.
There is a brief introduction to pulsejet engines and the three types of valve systems commonly used. Pulsejet calculator 1.4 not only incorporates the improved dimension calculator page, but also can give the flat sheet metal projection for all the parts of the tailpipe. The dimensions and layouts are created in both English and metric units for all three tailpipes needed to contain a valvesystem to produce a specific thrust.
The flat pattern projection dimensions created on the sheet metal layout page is a major help to people who want to roll the engine out of sheet metal. The cone section dimensions are normally hard to calculate by hand for each different cone, and very few people
actually make their cone flat patterns to the right dimensions forthis reason. The sheet metal layout page also allows you to calculate the weight of your pulsejet engine tailpipe by simply
entering the thickness of the metal being used (sheet metal gauge chart included for reference), and by entering the density of somesuitable alloys (you can choose from a list or enter your own).
The last page of the program allows you to generate the dimensionsof an exhaust cone or single cone augmenter. To generate the dimensions of the cone, enter data such as large and small diameters, and length of the cone. The weight calculator is also incorporated into this page. The next part on the augmenter and cone creator page supplies dimensions to make your own dual cone augmenter tube. The only data needed is intake diameter, intake length, throat diameter, exhaust length, and exhaust diameter. A short explanation of how to make the cone section and how to design the augmenter is also included in this page.
Obtaining the Pulsejet Calculator Program Pulsejet Calculator 1.4 is a free program, and can be used and freely distributed as long as it is not modified and it is kept in its entirety. Before I give step by step instructions 'right click'on the following link to download the program, and use the 'Save Target As' option to save it where you want to keep it:
点击下载:脉动式喷气发动机计算器

大量图片连接:http://www.tech-domain.com/thread-29708-1-77.html

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