The throat diameter of the steam ejector does have an effect on the suction pressure. The choice of throat diameter size directly affects the performance and working condition of the steam ejector. Smaller nozzle throat diameters will require relatively high operating vapor pressure when they reach normal operating condition. However, after reaching normal working conditions, the difference in the flow rate of the extracted steam between the injectors with different nozzle throat diameters is not large. In some cases, continuing to increase the pressure of the working steam will result in a slight decrease in the flow rate of the steam being pumped.
In addition, injectors with larger nozzle throat diameters typically have a wider operating range. This means that a larger throat diameter may help to better adapt to changes in suction pressure under the same operating conditions, thus improving the stability and efficiency of the system.
Therefore, when selecting a steam ejector, it is necessary to comprehensively consider the size of the nozzle throat according to the suction pressure requirements of the actual application and the overall performance requirements of the system. In practice, it is recommended to determine the optimal nozzle throat size through experiments or simulations according to the specific application scenario and process conditions to achieve the best suction effect and system performance.
What is the impact of the throat size of the steam ejector on the performance of the system
The size of the throat diameter of the steam ejector has a significant impact on the performance of the system. Here are a few of the main impacts:
Work efficiency
The size of the throat diameter directly affects the work efficiency of the injector. For example, when the nozzle throat diameter is a certain value (e.g. 2.5 mm), the injector may achieve maximum efficiency. This is because at this throat diameter, the pumped fluid has enough passage through the throat of the ejector, which increases the ejection coefficient and thus the work efficiency. However, when the throat diameter is too large or too small, it can lead to a decrease in work efficiency.
Boost ratio
The boost ratio is one of the important indicators to measure the performance of a steam ejector. The study shows that under different operating parameters, such as compressor frequency, condenser inlet water temperature and high-temperature evaporator inlet temperature, there is an optimal nozzle throat diameter, so that the injector boost ratio reaches the maximum value. When the throat diameter deviates from this optimal value, the boost ratio decreases significantly, which in turn affects the performance of the entire system.
Effective Boost Range
For different nozzle throat diameters, the injector has its own effective boost range. In this range, the injector is able to perform boosting operations efficiently. However, when the throat diameter is not suitable, it may cause the injector to lose its boost capacity at certain operating points, thus affecting the normal operation of the system.
Stability and reliability
The size of the throat also affects the stability and reliability of the steam ejector. If the throat diameter is not selected properly, it may cause problems such as vibration, noise or overheating during the operation of the injector, which in turn will affect the stability and service life of the system.
In summary, in order to achieve the best system performance, the optimal throat size of the steam ejector needs to be determined through experiments or simulations, depending on the specific application and process conditions. At the same time, other factors need to be considered, such as the pressure and temperature of the working steam, the nature of the pumped gas, etc., to ensure that the steam ejector can operate efficiently and stably under various working conditions.
