Preliminary Study of a Novel R718 Compression Refrigeration Cycle Using a Three-Port Condensing Wave Rotor

2005 ◽  
Vol 127 (3) ◽  
pp. 539-544 ◽  
Author(s):  
Amir A. Kharazi ◽  
Pezhman Akbari ◽  
Norbert Mu¨ller
Keyword(s):  
Performance Enhancement ◽  
Pressure Ratio ◽  
Refrigeration Cycle ◽  
Wave Rotor ◽  
Flash Evaporation ◽  
Pressurized Water ◽  
Performance Map ◽  
Wave Compression ◽  
Preliminary Study ◽  
Shock Wave Compression

Using a novel 3-port condensing wave rotor enhancing the turbocompression in a R718 refrigeration cycle, which uses only water as a refrigerant, has been introduced. The wave-rotor implementation can increase efficiency and reduce size and cost of R718 units. The condensing wave rotor employs pressurized water to pressurize, desuperheat, and condense the refrigerant vapor—all in one dynamic process. The underlying phenomena of flash evaporation, shock wave compression, desuperheating, and condensation inside the wave rotor channels are described in a wave and phase-change diagram. The thermodynamic process is shown in pressure–enthalpy and temperature–entropy diagrams. A computer program based on a thermodynamic model was generated to evaluate the performance of R718 baseline and wave-rotor-enhanced cycles. The effect of some key parameters on the performance enhancement is demonstrated as an aid for optimization. A performance map summarizes the findings. It shows optimum wave rotor pressure ratio and maximum relative performance improvement of R718 cycles by using the 3-port condensing wave rotor.

Preliminary Study of a Novel R718 Turbo-Compression Cycle Using a 3-Port Condensing Wave Rotor

2004 ◽  
Author(s):  
Amir A. Kharazi ◽  
Pezhman Akbari ◽  
Norbert Mu¨ller
Keyword(s):  
Performance Enhancement ◽  
Pressure Ratio ◽  
Wave Rotor ◽  
Flash Evaporation ◽  
Pressurized Water ◽  
Compression Cycle ◽  
Performance Map ◽  
Wave Compression ◽  
Preliminary Study ◽  
Shock Wave Compression

Using a novel 3-port condensing wave rotor enhancing the turbo-compression in a R718 refrigeration cycle, which uses only water as a refrigerant, has been introduced. The wave-rotor implementation can increase efficiency and reduce size and cost of R718 units. The condensing wave rotor employs pressurized water to pressurize, desuperheat, and condense the refrigerant vapor — all in one dynamic process. The underlying phenomena of flash evaporation, shock wave compression, desuperheating, and condensation inside the wave rotor channels are described in a wave and phase-change diagram. The thermodynamic process is shown in pressure-enthalpy and temperature-entropy diagrams. A computer program based on a thermodynamic model was generated to evaluate the performance of R718 baseline and wave-rotor-enhanced cycles. The effect of some key parameters on the performance enhancement is demonstrated as an aid for optimization. A performance map summarizes the findings. It shows optimum wave rotor pressure ratio and maximum relative performance improvement of R718 cycles by using the 3-port condensing wave rotor.

Implementation of 3-Port Condensing Wave Rotors in R718 Cycles

2005 ◽  
Vol 128 (4) ◽  
pp. 325-334 ◽  
Author(s):  
Amir A. Kharazi ◽  
Pezhman Akbari ◽  
Norbert Müller
Keyword(s):  
Performance Improvement ◽  
Performance Enhancement ◽  
Pressure Ratio ◽  
Wave Rotor ◽  
Flash Evaporation ◽  
Pressurized Water ◽  
Wave Rotors ◽  
Performance Map ◽  
Wave Compression ◽  
Shock Wave Compression

The use of a novel 3-port condensing wave rotor is suggested to enhance the turbocompression in a refrigeration cycle that works only with water (R718) as a refrigerant. Although the implementation of such a wave rotor essentially reduces the size and cost of R718 units, their efficiency may also be increased. The condensing wave rotor employs pressurized water to pressurize, desuperheat, and condense the refrigerant vapor, all in one dynamic process. The underlying phenomena of flash evaporation, shock wave compression, desuperheating, and condensation inside the wave rotor channels are described in a wave and phase-change diagram. The thermodynamic process is shown in pressure-enthalpy and temperature-entropy diagrams. Based on the described thermodynamic model, a computer program was generated to evaluate the performance of R718 baseline and wave-rotor-enhanced cycles. The effect of some key parameters on the performance enhancement is demonstrated as an aid for optimization. A performance map summarizes the findings. It shows optimum wave rotor pressure ratio and maximum relative performance improvement of R718 cycles by using the 3-port condensing wave rotor.

Performance Benefits of R718 Turbo-Compression Cycle Using 3-Port Condensing Wave Rotors

2004 ◽  
Author(s):  
Amir A. Kharazi ◽  
Pezhman Akbari ◽  
Norbert Mu¨ller
Keyword(s):  
Performance Enhancement ◽  
The Novel ◽  
Wave Rotor ◽  
Flash Evaporation ◽  
Pressurized Water ◽  
Wave Rotors ◽  
Compression Cycle ◽  
Performance Map ◽  
Wave Compression ◽  
Novel Concept

A number of technical challenges have often hindered the economical application of refrigeration cycles using water (R718) as refrigerant. The novel concept of condensing wave rotor provides a solution for performance improvement of R718 refrigeration cycles. The wave rotor implementation can increase efficiency and reduce the size and cost of R718 units. The condensing wave rotor employs pressurized water to pressurize, desuperheat, and condense the refrigerant vapor — all in one dynamic process. In this study, the underlying phenomena of flash evaporation, shock wave compression, desuperheating, and condensation inside the wave rotor channels are described in a wave and phase-change diagram. A computer program based on a thermodynamic model is generated to evaluate the performance of R718 baseline and wave-rotor-enhanced cycles. The detailed thermodynamic approach for the baseline and the modified cycles is described. The effect of some key parameters on the performance enhancement is demonstrated as an aid for optimization. A generated performance map summarizes the findings.

Utilizing Wave Rotor Technology to Enhance the Turbo Compression in Power and Refrigeration Cycles

2003 ◽  
Author(s):  
Pezhman Akbari ◽  
Amir A. Kharazi ◽  
Norbert Mu¨ller
Keyword(s):  
Power Generation ◽  
Dynamic Process ◽  
State Of The Art ◽  
Pressure Ratio ◽  
Refrigeration Cycle ◽  
Specific Work ◽  
Wave Rotor ◽  
Pressurized Water ◽  
Wave Rotors ◽  
Overall Efficiency

The objective of this paper is to review and suggest wave-rotor applications in power generation and refrigeration systems. The emphasis is on recent investigations performed by the authors for a microturbine (30 kW) and a novel enhancement of a state-of-the-art water (R718) compression refrigeration cycle. The results of thermodynamic analyses performed for the small gas turbine topped with a 4-port wave rotor show that engine overall efficiency and specific work may increase by up to about 33% without changing the compressor. Expecting similar advantages, it is suggested to use wave rotors in novel R718 compression refrigeration systems. This also introduces a new concept of a condensing wave-rotor that employs pressurized water to both (1) additional rise the pressure of the vapor and (2) desuperheat and condense it, all in one dynamic process. Adding the condensing wave-rotor to the refrigeration cycle allows for a lower pressure ratio of the compressor, which is crucial for the R718 chiller technology. Some structural and economic advantages of the proposed system are mentioned.

Thermodynamic Analysis a Novel Wave Rotor Refrigeration Cycle

2013 ◽  
Vol 805-806 ◽  
pp. 537-542 ◽  
Author(s):  
Jia Quan Zhao ◽  
Da Peng Hu ◽  
Pei Qi Liu ◽  
Feng Xia Liu ◽  
Jin Ji Gao
Keyword(s):  
Pressure Wave ◽  
Simple Structure ◽  
Pressure Ratio ◽  
Energy Transfer Efficiency ◽  
Refrigeration Cycle ◽  
Wave Rotor ◽  
Expansion Process ◽  
Compression Process ◽  
Compression Efficiency ◽  
Experimental Works

As a novel generation of thermal separators, the Wave rotor refrigerator (WRR) has replaced the traditional pressure-wave thermal separator. However, the isentropic refrigeration efficiency still needs to be improved compared with expander. A novel WRR system cycle was built and the system performance was thermal analyzed under various parameters, such as expansion efficiency or compression efficiency of wave rotor. The results are used to compare with the traditional WRR system. It is shown that the advantage provided by this novel cycle over the traditional WRR is an expansion process and a compression process is integrated into one unit, with a higher energy transfer efficiency and simple structure. The isentropic refrigeration efficiency of this novel cycle can be more than twice of the traditional WRR under the pressure ratio of 1.1. The experimental works are carrying out.

Performance Enhancement of One and Two-Shaft Industrial Turboshaft Engines Topped With Wave Rotors

2018 ◽  
Vol 35 (2) ◽  
pp. 137-147 ◽  
Author(s):  
Antonios Fatsis
Keyword(s):  
Gas Turbines ◽  
Performance Enhancement ◽  
Pressure Ratio ◽  
Inlet Temperature ◽  
Specific Work ◽  
Wave Rotor ◽  
Wave Rotors ◽  
Compressor Pressure Ratio ◽  
Industrial Gas Turbines ◽  
The One

Abstract Wave rotors are rotating equipment designed to exchange energy between high and low enthalpy fluids by means of unsteady pressure waves. In turbomachinery, they can be used as topping devices to gas turbines aiming to improve performance. The integration of a wave rotor into a ground power unit is far more attractive than into an aeronautical application, since it is not accompanied by any inconvenience concerning the over-weight and extra dimensioning. Two are the most common types of ground industrial gas turbines: The one-shaft and the two-shaft engines. Cycle analysis for both types of gas turbine engines topped with a four-port wave rotor is calculated and their performance is compared to the performance of the baseline engine accordingly. It is concluded that important benefits are obtained in terms of specific work and specific fuel consumption, especially compared to baseline engines with low compressor pressure ratio and low turbine inlet temperature.

Performance Improvement of Small Gas Turbines Through Use of Wave Rotor Topping Cycles

2003 ◽  
Author(s):  
Pezhman Akbari ◽  
Norbert Mu¨ller
Keyword(s):  
Gas Turbines ◽  
Performance Enhancement ◽  
Pressure Ratio ◽  
Inlet Temperature ◽  
Wave Rotor ◽  
Advantages And Disadvantages ◽  
Turbine Inlet ◽  
Compressor Pressure Ratio ◽  
Significant Performance ◽  
Almost All

Results are presented predicting the significant performance enhancement of two small gas turbines (30 kW and 60 kW) by implementing various wave rotor topping cycles. Five different advantageous implementation cases for a four-port wave rotor into given baseline engines are considered. The compressor and turbine pressure ratios, and the turbine inlet temperatures vary in the thermodynamic calculations, according to the anticipated design objectives of the five cases. Advantages and disadvantages are outlined. Comparison between the theoretic performance (expressed by specific cycle work and overall thermal efficiency) of wave-rotor-topped and baseline engines shows a performance enhancement by up to 33%. The results obtained show that almost all the cases studied benefit from the wave-rotor-topping, but the highest gain is obtained for the case in which the topped engine operates with the same turbine inlet temperature and compressor pressure ratio as the baseline engine. General design maps are generated for the small gas turbines, showing the design space and optima for baseline and topped engines.

Advanced Supersonic Component Engine for Military Applications

2007 ◽  
Author(s):  
Shawn P. Lawlor ◽  
Robert C. Steele ◽  
Peter Baldwin
Keyword(s):  
Shock Wave ◽  
Gas Turbines ◽  
High Speed ◽  
Size Range ◽  
Pressure Ratio ◽  
Fuel Efficiency ◽  
Axial Flow ◽  
Direct Drive ◽  
Wave Compression ◽  
Shock Wave Compression

A 1500 kWe Brayton cycle engine is in development that has the efficiency of a diesel, but with the size, weight and maintenance attributes of a gas turbine. The Advanced Supersonic Component Engine (ASCE) combines many of the proven features of shock wave compression and expansion systems, commonly used in supersonic flight inlet and nozzle designs, with turbo-machinery practices employed in conventional axial flow gas turbines. The superior efficiency of the ASCE is a result of high pressure shock wave compression and supersonic expansion phenomena that produce high component efficiencies and a unique engine configuration that minimizes flow stream turning losses throughout the system. The engine employs a two stage counter-rotating configuration to achieve a 30:1 pressure ratio and a 42% simple cycle efficient engine to drive a high-speed direct drive permanent magnet (PM) electric motor/generator for all electric power and propulsion applications. The system promises a specific fuel consumption equal to or better than current reciprocating diesel engines in this size range, but with a 10:1 weight reduction and a 4:1 improvement in time-between-overall compared to marine diesel systems in this size range. This is a 2:1 increase in fuel efficiency at full power over existing gas turbines in this size range.

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