Experimental investigation on motive nozzle throat diameter for an ejector expansion refrigeration system

2016 ◽  
Vol 124 ◽  
pp. 1-12 ◽  
Author(s):  
Nagihan Bilir Sag ◽  
H. Kursad Ersoy
Author(s):  
Jingming Dong ◽  
D. A. Pounds ◽  
P. Cheng ◽  
H. B. Ma

A steam ejector refrigeration system with a movable primary nozzle was developed in order to determine the nozzle exit position (NXP) effect on the coefficient of performance (COP). Experimental results show that there exists an optimum NXP for the ejector system investigated herein. The effects of the operating temperature, diffuser size, nozzle throat diameter, and mixing chamber configuration on the COP and critical back pressure were investigated experimentally. It is found that the critical back pressure and COP can be increased by increasing the low temperature evaporator (LTE) temperature and pressure. Although an increase of the high temperature evaporator (HTE) temperature can increase the critical condenser pressure, the system COP does not increase as the HTE temperature increases. The diffuser size significantly affects the critical back pressure but had almost no effect on the system COP. A finned mixing chamber was tested at NXP = 0 mm and NXP = 36 mm. Compared with the regular mixing chamber, the finned mixing chamber can increase the critical back pressure.


2015 ◽  
Vol 667 ◽  
pp. 449-454
Author(s):  
Yang Hong ◽  
Xiang Zhang ◽  
Dong Xiang Shao ◽  
Guang Lin Wang ◽  
Li Sun

This paper proposes a hydraulic measurement model for measuring the Laval nozzle throat diameter size. Based on measurement principle of liquid pressure – flowrate, we can get the size of Laval nozzle throat diameter by measuring the fluid flowrate through hydraulic measurement model at the fixed pressure. With good viscosity-temperature performance, low temperature performance and oxidation stability, UCBO aviation hydraulic oil is selected as the measuring medium. In the hydraulic measurement model, the diameter of the mandrel which can be regarded as gauge will directly affect the sensitivity of diameter measurement. Therefore we need to optimize the design of the mandrel of the hydraulic model.


Author(s):  
Vikas Kumar ◽  
Gulshan Sachdeva ◽  
Sandeep Tiwari ◽  
Parinam Anuradha ◽  
Vaibhav Jain

A conventional vapor compression refrigeration system (VCRS) cascaded with a heat-assisted ejector refrigeration system (ERS) has been experimentally analyzed. Cascading allows the VCRS to operate at lower condenser temperatures and thus achieve a higher coefficient of performance. In this cascaded system, the condenser of the vapor compression system does not dissipate its heat directly to the evaporator of the ERS; instead, water circulates between the condenser of VCRS and the evaporator of ERS to exchange the heat. Seven ejectors of different geometries have been used in the ERS; however, all the ejectors could not maintain thermal equilibrium at the desired operating conditions. The compressor of the cascaded VCRS consumed 1.3 times less power than the noncascaded VCRS. Furthermore, the cascaded system provided a maximum 87.74% improvement in COP over the noncascaded system for the same operating conditions. The performance of the system remained constant until the critical condenser pressure of the ERS.


Sign in / Sign up

Export Citation Format

Share Document