The performance characteristics of an ejector-expansion refrigeration cycle (EEC) using R32 have been investigated in comparison with that using R134a. The coefficient of performance (COP), the exergy destruction, the exergy efficiency and the suction nozzle pressure drop (SNPD) are discussed. The results show that the application of an ejector instead of a throttle valve in R32 cycle decreases...

This paper reports a novel actuating design that uses the shear deformation of a piezoelectric actuator to deflect a bulge-diaphragm for driving an array microdroplet ejector. In essence, we employed a circular-shaped actuator poled radial direction with remnant polarization normal to the actuating electric field for inducing the piezoelectric shear effect. The array microdroplet ejector consis...

This paper reports a novel actuating design that uses the shear deformation of a piezoelectric actuator to deflect a bulge-diaphragm for driving an array microdroplet ejector. In essence, we employed a circular-shaped actuator poled radial direction with remnant polarization normal to the actuating electric field for inducing the piezoelectric shear effect. The array microdroplet ejector consis...

Optimization of a High-Efficiency Jet Ejector by Computational Fluid Dynamics Software. (May 2005) Somsak Watanawanavet, B.S., Chulalongkorn University Co-Chairs of Advisory Committee: Dr. Mark T. Holtzapple Dr. Charles J. Glover Research was performed to optimize high-efficiency jet ejector geometry (Holtzapple, 2001) by varying nozzle diameter ratios from 0.03 to 0.21, and motive velocities f...

The article deals with pneumatic and hot wire anemometry measurement on subsonic axi-symmetric air ejector. Performances of the ejector with and without pulsations of primary flow are compared, measuring of characteristic pressures and mass flow rates are performed and ejector efficiency is evaluated. The pulsations of primary flow are produced by a synthetic jet generator, which is placed in t...

In this paper the supersonic ejectors are experimentally and analytically studied. Ejector is a device that uses the energy of a fluid to move another fluid. This device works like a vacuum pump without usage of piston, rotor or any other moving component. An ejector contains an active nozzle, a passive nozzle, a mixing chamber and a diffuser. Since the fluid viscosity is large, and the flow is...

ANSI/ASHRAE Standard 110 provides a quantitative method for testing the performance of laboratory fume hoods. Through release of a known quantity (4.0 Lpm) of a tracer gas, and subsequent monitoring of the tracer gas concentration in the "breathing zone" of a mannequin positioned in front of the hood, this method allows for evaluation of laboratory hood performance. Standard 110 specifies sulfu...

In this work, a novel dual-nozzle ejector enhanced triple-evaporator refrigeration cycle (DETRC) without separator is proposed to improve the performance of the conventional ejector one (CETRC). The performance of DETRC is analyzed and compared with CETRC in term of energy coefficient of performance (COPen). Under given operating conditions, the COPen improvement of the no...

Ejector refrigeration is a promising technology for the integration into solar driven cooling systems because of its relative simplicity and low initial cost. The major drawback of such a system is associated with its relatively low coefficient of performance (COP) under variable operating conditions. In order to overcome this problem, an advanced ejector was developed that changes its geometri...

This paper summarizes the numerical analysis of a liquid-liquid ejector pump with focus on the accuracy of the employed cavitation model and in view of its potential application as a dualor multi-liquid mixing and injection system. While the use of gas-phase or gas/liquid-phase ejection systems has found wide application in gas/hybrid burners and scrubbers for air pollution control; the use of ...