An investigation of some design factors of a steam jet refrigeration unit

A series of tests was run to determine the performance characteristics of the 2-1/2 ton steam jet refrigeration unit. The first series of tests was run to determine the nozzle position relative to the throat of the diffuser at which best performance was obtained. This series included tests with two methods of introducing the warm water into the evaporator, namely by spraying the warm water into the evaporator by means of commercial spray nozzles and by spraying the warm water into the evaporator through small holes in a straight piece of pipe. A series of tests was run to determine the effect of the evaporator water level on performance. A series of tests was also run with inlet steam pressures lower and higher than design in combination with outlet pressures at and lower than design. Lastly, one test was run in an effort to reduce the amount of liquid carryover into the ejector. From the results of the above tests the following was concluded: 1. Use of a 62% entrainment efficiency and a 65% diffuser efficiency to give a greater steam flow rate did not enable the design capacity to be met. 2. Best performance of the unit was obtained with the nozzle exit 7-1/2 inches from the entrance to the diffuser throat. 3. Better performance was obtained from the unit by introducing the wara water into the evaporator by means of the commercial spray nozzles than was obtained by introducing the warm water into the evaporator by means of small hole in a straight pipe. 4. Lowering the evaporator water level did not effect performance of the unit greatly. However, control of the unit was greatly enhanced by using a low evaporator water level. 5. Performance of the unit was unstable at inlet steam pressures above design and outlet pressure below design. The capacity of the unit dropped sharply under these condition 6. The design evaporator outlet velocity was too high to enable a sufficiently large amount of liquid carryover to be baffled out. 7. The compression process in the diffuser did not occur as assumed in the design procedure. 8. The throat area of the diffuser should be increased to reduce the fluid velocity in the throat and thereby improve performance of the unit. This is necessary to make the normal shock occur at the throat section of the diffuser.

Name thesis:degree_name

M.S.

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Mechanical Engineering

Department dc:contributor.department

Mechanical Engineering

Grantor dc:publisher

Virginia Polytechnic Institute

Year dc:date.issued

1954

Author dc:creator

• Brehm, Robert Luther

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Handle dc:identifier.uri

http://hdl.handle.net/10919/104266

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/104266