What should the pressure be at the ejector nozzle in a steam jet cooling system?

What should the pressure be at the ejector nozzle in a steam jet cooling system?

• A. 150 psia
• B. 50 psia
• C. 300 psia
• D. 1 atm

Answer: (A)

In a steam jet cooling system, the ejector nozzle needs motive steam with enough energy to create a high-velocity jet that can entrain other vapor and establish the low-pressure region in the mixing chamber. This requires a fairly high absolute pressure at the nozzle entry. Around 150 psia absolute is typical for providing that jet energy while staying within standard steam supply conditions. If the pressure were only atmospheric, the jet wouldn’t have enough velocity to pull in vapor; if it were as low as 50 psia, the jet energy would be insufficient; and if it were as high as 300 psia, it would be unnecessarily aggressive and may stress components. Therefore, about 150 psia is the best balance for proper ejector operation.

In a steam jet cooling system, the ejector nozzle needs motive steam with enough energy to create a high-velocity jet that can entrain other vapor and establish the low-pressure region in the mixing chamber. This requires a fairly high absolute pressure at the nozzle entry. Around 150 psia absolute is typical for providing that jet energy while staying within standard steam supply conditions. If the pressure were only atmospheric, the jet wouldn’t have enough velocity to pull in vapor; if it were as low as 50 psia, the jet energy would be insufficient; and if it were as high as 300 psia, it would be unnecessarily aggressive and may stress components. Therefore, about 150 psia is the best balance for proper ejector operation.