Post-Reading

 

I. In the text find definitions for the following terms:

 

- angle of attack

- angle of incidence

- a choking action

 

II. Find the Russian equivalents to the following words and word combinations from the text:

	-to be affected; to be viewed; to be confused; destroy; discharge; to be slowed down; to handle; result from - leading edge; cascade affect; placement; stall; incidence; schedule; prime action; choking; excess volume; ram effect; square root; tendency; - vital; turbulent; relative; excessive - since; rather than; due to; in general

 

III. Complete the following sentences using the ideas from the text.

 

1. This “cascade” effect can be more readily understood if...

2. The angle of attack will vary with...

3.... will increase the angle of attack and increase the tendency to stall.

4. If the engine speed is decreased from the design speed, the compression ratio will...

5. High-speed aircraft may experience...

6. High compressor inlet temperatures will cause the length of the airflow vector to...

7. On compressor inlet pressure may become too low in respect to...

 

IV. Match the begining of the sentence with its ending using the ideas from the text.

 

1. This “cascade” effect is	a) a fixed angle determined by the manufacture when the compressor is constructed.
2. The angle of attack is	b) the pressure zones will be high and airflow and compression ratio will be high.
3. The angle of incidence is	c) will tend to increase the angle of attack.
4. If the angle of attack is high,	d) which in turn decreases the air velocity in the front of the compressor and increases the tendency to stall.
5. Decreasing the velocity of airflow or increasing engine rotor speed	e) that caused by low compression ratio due to low engine speeds.
6. The excess volume of air causes a choking action in the rear of the compressor with a decrease in airflow,	f) viewed as flow through a series of ducts formed by the individual blades.
7. The choking stall condition is the same as	g) the angle at which the airflow strikes the rotor blades.

 

IV. Explain the meaning of the words marked in the text in English.

 

VI. a)Answer the following questions according to the text.

1. What does an axial flow compressor consist of?

2. What is a cascade affect?

3. What is the vital problem of a compressor?

4. At what conditions does the compressor stall occur?

5. What is the prime action that tends to cause a stall during ground operation?

 

b) Think of 3 more questions to the text.

 

Language in Use

I. Match pairs of synonyms.

 

 

 

 

 

II. Match pairs of antonyms.

 

III. Use the prepositions in the oval to complete the sentences in the text. Translate the text with the help of a dictionary in written.

 

 

 

This characteristic has been called both " Surge " and " Stall " _____the past, but is more properly called SURGE when it is response _____ the entire engine. The word stall applies_____ the action occurring at each individual compressor blade. Compressor surge, also called Compressor stall, is a phenomenon which is difficult to understand because it is usually caused _____complex combination of factors. The basic cause of compressor surge is fairly simple. Each blade _____an axial flow compressor is a miniature airplane wing, which, when subjected _____a higher angle of attack, will stall just as an airplane stalls. Surge may be defined as results_____ an unstable air condition _____the compressor. The unstable condition of air is often caused _____air piling up _____the rear stages of the compressor. Surge may cause loud bangs and engine vibration. In most cases, this condition is of short duration, and will either correct itself or can be corrected _____ retarding the throttle or power lever to idle and advancing it again, slowly.

IV. Insert the words into gaps.

 

 

 

 

A method of _____ onset of a gas turbine condition, such as compressor stall, includes receiving data indicative of an operating parameter of a compressor of the gas turbine. The method also includes performing a wavelet transformation on the data to generate wavelet transformed data. The wavelet _____ is configured to affect a processing characteristic regarding a performance of the wavelet transformation. Features indicative of onset of the gas turbine condition in the wavelet transformed data are then

_____ to provide an indication for controlling the gas turbine to prevent compressor stall from occurring. A system for detecting onset of compressor stall in a gas turbine includes a _____ for providing data indicative of an operating parameter of the compressor and a _____ for performing a wavelet transform on the data to identify features of the optimized wavelet transformed data indicative of onset of stall.

 

 

Writing

Summarize the information given in the text «Compressor Stall». Use the key-patterns.

 

 

 

Unit IV.