RU1800135C - Method of isobaric ejector operation - Google Patents

Abstract

SUMMARY OF THE INVENTION: High-pressure and low-pressure jets are mixed in the initial portion of the mixing chamber at constant static pressure. A low pressure jet is fed to the initial portion of the chamber at a reduced speed determined from a mathematical expression. 2 ill.

Description

The invention relates to inkjet technology and can be used in various fields of national economy (aviation, chemical, gas industry, heat power engineering, cryogenic and vacuum technology).

The purpose of the invention is to increase the efficiency of the isobaric ejector.

FIG. 1 - ejector; FIG. 2 is a graph of efficiency versus reduced initial velocity for a series of values of the characteristic pressure ratio cpri, 2.

The ejector contains a coaxially mounted supersonic high-pressure nozzle 1, a mixing chamber with an inlet and cylindrical outlet sections 3.4 and a diffuser 5. The inlet section 3 of the mixing chamber 2 is made in the form of a diffuser, smoothly connected to the cylindrical section 4, while the input section of the diffuser section 3 is located in the cut plane of the exit section of the nozzle 1. When the ejector is operating, the low-pressure medium entering the initial diffuser section 3 is mixed with a velocity other than zero to the high-pressure jet expiring from nozzle 1. The process takes place at almost

constant static pressure. An uneven stream formed with the mixture enters through a smooth transition into the cylindrical outlet section 4 of the mixing chamber 2, where the mixing of the working fluid is completed and the supersonic mixture is decelerated in the shock waves. The subsonic mixture flow emerging from the outlet cylindrical section 4 is inhibited in the expanding diffuser 5. It has been experimentally established that for each value of the ejection coefficient there is an optimal value of the reduced velocity of the low-pressure jet irrespective of other parameters of the ejector.

The advantage of the proposed method of operation of the isobaric ejector associated with the choice of the reduced initial velocity of the low-pressure jet, depending on the ejection coefficient from the mathematical expression

Ah, ak;

, 6-0.9

, 25-0.45,

illustratively illustrated in FIG. 2. Here are the dependences of the efficiency of the hedge00

oh oh

Cj

ate

torus from the reduced initial velocity for a number of values of the characteristic pressure ratio st (from a 10 to 1000) at, 2

As can be seen from FIG. 2, the optimum reduced velocity of the low-pressure jet irrespective of is within the range of 0.4-0.45.

Thus, the proposed method of operation of an isobaric ejector provides an increase in the efficiency of the ejector in a wide range of operating parameters.

Claims (1)

The claims The method of operation of the isobaric ejector, including mixing vysokon2. pore and low-pressure jets in the initial section of the mixing chamber at constant static pressure, characterized in that the low-pressure jet is fed to the initial section of the mixing chamber with a reduced speed determined from a mathematical expression , where AI is the initial initial velocity of the low-jet jet; K is the ejection coefficient; a 0.60-0.90; b 0.25-0.45. 5