THEORETICAL EVALUATION OF LOUDSPEAKER FOR A 10 WATTS COOLING POWER THERMOACOUSTIC REFRIGERATOR

2013 ◽  
Vol 21 (04) ◽  
pp. 1350027 ◽  
Author(s):  
B. G. PRASHANTHA ◽  
M. S. GOVINDE GOWDA ◽  
S. SEETHARAMU ◽  
G. S. V. L. NARASIMHAM
Keyword(s):  
Acoustic Resonator ◽  
Cooling Power ◽  
Electrical Model ◽  
Force Factor ◽  
Theoretical Evaluation ◽  
Back Volume ◽  
Resonator Frequency ◽  
Spring System ◽  
Good Agreement ◽  
Thermoacoustic Refrigerator

This paper presents a design of moving coil loudspeaker for a 10 W cooling power thermoacoustic refrigerator. An electrical model is presented which simulates the behavior of the loudspeaker. The gas spring system for matching the frequency of the commercially available loudspeaker with the frequency of the acoustic resonator tube for maximizing electro-acoustical efficiency of the loudspeaker is discussed. The optimum back volume for the gas spring system is found to be 59.7 cc, which is about 1.9% of the total resonator volume when the loudspeaker frequency and the acoustic resonator frequency is made equal at 400 Hz with a moving mass of 20 g. The effect of force factor Bl on loudspeaker performance is discussed. Analysis results shows that for better performance of a refrigerator, the loudspeaker should be chosen to have a large force factor and small values for electrical and mechanical resistances. The refrigerator system is tested with DeltaEC software and its results are in good agreement with an electrical model results.

Theoretical Evaluation of a 10-Watt Cooling Power Thermoacoustic Refrigerator

2013 ◽  
Vol 43 (7) ◽  
pp. 577-591 ◽  
Author(s):  
B.G. Prashantha ◽  
M.S. Govinde Gowda ◽  
S. Seetharamu ◽  
G.S.V.L. Narasimham
Keyword(s):  
Cooling Power ◽  
Theoretical Evaluation ◽  
Thermoacoustic Refrigerator

DESIGN AND OPTIMIZATION OF A LOUDSPEAKER DRIVEN 10-W COOLING POWER THERMOACOUSTIC REFRIGERATOR

2014 ◽  
Vol 22 (03) ◽  
pp. 1450015 ◽  
Author(s):  
B. G. PRASHANTHA ◽  
M. S. GOVINDE GOWDA ◽  
S. SEETHARAMU ◽  
G. S. V. L. NARASIMHAM
Keyword(s):  
Surface Area ◽  
Optimization Procedure ◽  
Cooling Power ◽  
Design And Optimization ◽  
Resonator Design ◽  
Quarter Wavelength ◽  
Optimum Diameter ◽  
Minimum Heat ◽  
Good Agreement ◽  
Thermoacoustic Refrigerator

The design and optimization procedure for a loudspeaker driven 10-W cooling power thermoacoustic refrigerator components with a temperature difference of 120 K has been discussed using the linear thermoacoustic theory. The resonator losses are proportional to surface area and the optimum diameter ratio of small and large resonator tubes for minimum heat loss for a quarter-wavelength hemispherical ended resonator design is discussed. The hemispherical ended resonator design is further analytically optimized to increase COP, cooling effect at cold heat exchanger and power density by decreasing total resonator surface area and volume. An alternate convergent-divergent resonator design is proposed which is found to be more efficient compared to previous published designs. Resonator designs are tested with DeltaEC software, which predicts a lowest temperature of -48°C and -47°C for the improved hemispherical and convergent-divergent resonator designs, respectively. Theoretical results are in good agreement with DeltaEC results.

Resonator Optimization and Studying the Effect of Drive Ratio on the Theoretical Performance of a 10-W Cooling Power Thermoacoustic Refrigerator

2015 ◽  
Vol 23 (03) ◽  
pp. 1550020 ◽  
Author(s):  
B. G. Prashantha ◽  
M. S. Govinde Gowda ◽  
S. Seetharamu ◽  
G. S. V. L. Narasimham
Keyword(s):  
Dynamic Pressure ◽  
Optimization Procedure ◽  
Cooling Power ◽  
Pressure Amplitude ◽  
Performance Simulation ◽  
Resonator Design ◽  
Working Principle ◽  
Simulation Results ◽  
Theoretical Performance ◽  
Thermoacoustic Refrigerator

This paper deals with the basic insight of thermoacoustic refrigeration concepts, and the working principle, history and the role of linear thermoacoustic theory in designing a thermoacoustic refrigerator system are discussed. Resonator design optimization procedure for a 10W cooling power thermoacoustic refrigerators is discussed. The optimized resonator designs proposed in this paper are found to be efficient compared to published resonator designs. The effects of drive ratio on the theoretical performance by varying dynamic pressure amplitude from 0.2 bar to 0.4 bar in the steps of 0.05 bar on the optimized resonator designs are discussed. Performance simulation results for the optimized resonator designs using DeltaEC software are discussed. Simulation results are in agreement with theoretical results.

DESIGN AND ANALYSIS OF THERMOACOUSTIC REFRIGERATOR

2013 ◽  
Vol 21 (01) ◽  
pp. 1350001 ◽  
Author(s):  
B. G. PRASHANTHA ◽  
M. S. GOVINDE GOWDA ◽  
S. SEETHARAMU ◽  
G. S. V. L. NARASIMHAM
Keyword(s):  
Boundary Layer ◽  
Power Density ◽  
Gas Pressure ◽  
Coefficient Of Performance ◽  
Cooling Power ◽  
Boundary Layer Approximation ◽  
Resonator Design ◽  
Quarter Wavelength ◽  
Calculation Results ◽  
Thermoacoustic Refrigerator

This paper deals with the design and analysis of a quarter-wavelength, 10 W capacity, thermoacoustic refrigerator using short stack boundary layer approximation assumptions. The effect of operating frequency on the performance of the refrigerator is studied using dimensional normalization technique. The variation of stack diameter with average gas pressure and cooling power is discussed. The resonator optimization is discussed and the calculation results show a 9% improvement in the coefficient of performance and 201% improvement in power density for the optimized quarter-wavelength resonator compared to published optimization studies. The optimized resonator design is tested with DeltaEC software and the results show better performance compared to past established resonator designs.

scholarly journals Theoretical Evaluation of Ultrasonic Velocities of Binary Liquid Mixtures of 1-Bromopropane in Chlorobenzene at 303.15, 308.15, 313.15 and 318.15 K

2014 ◽  
Vol 30 ◽  
pp. 9-17
Author(s):  
Ch. Praveen Babu ◽  
G. Pavan Kumar ◽  
B. Nagarjun ◽  
K. Samatha
Keyword(s):  
Intermolecular Interactions ◽  
Theoretical Models ◽  
Liquid Mixtures ◽  
Binary Liquid Mixtures ◽  
Ultrasonic Velocities ◽  
Theoretical Evaluation ◽  
Binary Liquid ◽  
Different Temperatures ◽  
Experimental Values ◽  
Good Agreement

Theoretical velocities of binary liquid mixtures of 1-bromopropane with chlorobenzene at 2 MHz and four different temperatures 303.15, 308.15, 313.15 and 318.15 K, have been evaluated as a function of concentration and temperature. The experimental values are compared with theoretical models of liquid mixtures such as Nomoto, Van Dael-Vangeel, Impedance Relation, Rao’s Specific Velocity Method, Junjie’s relations and Free Length Theory. In the chosen system there is a good agreement between experimental and theoretical values calculated by Nomoto’s theory. The deviation in the variation of U2exp/U2imx from unity has also been evaluated for explaining the non ideality in the mixtures. The results are explained in terms of intermolecular interactions occurring in these binary liquid mixtures.

scholarly journals Experimental and Theoretical Evaluation of Ultrasonic Velocities of Binary Liquid Mixtures of Anisaldehyde and Toluene at Different Temperatures

2011 ◽  
Vol 8 (3) ◽  
pp. 977-981
Author(s):  
CH. Srinivasu ◽  
K. Narendra ◽  
CH. Kalpana
Keyword(s):  
Ultrasonic Velocity ◽  
Theoretical Models ◽  
Liquid Mixtures ◽  
Binary Liquid Mixtures ◽  
Ultrasonic Velocities ◽  
Theoretical Evaluation ◽  
Binary Liquid ◽  
Different Temperatures ◽  
Experimental Values ◽  
Good Agreement

Theoretical velocities of binary liquid mixtures of anisaldehyde with toluene at 303.15, 308.15, 313.15 and 318.15 K have been evaluated by using theoretical models of liquid mixtures such as Nomoto, Van Dael-Vangeel, Schaff’s collision factor theory and Junjie’s relations. Density and ultrasonic velocity of these mixtures have also been measured as a function of concentration and temperature and the experimental values are compared with the theoretical values. A good agreement has been found between experimental and Nomoto’s theoretical ultrasonic velocities. The results are explained in terms of intermolecular interactions occurring in these binary liquid mixtures.

A THEORETICAL EVALUATION OF THE NITROGEN ISOTOPE EFFECT IN THE THERMAL DEAMMONATION OF PHTHALAMIDE

1952 ◽  
Vol 30 (5) ◽  
pp. 443-447 ◽  
Author(s):  
Jacob Bigeleisen
Keyword(s):  
Theoretical Analysis ◽  
Isotope Effect ◽  
Nitrogen Isotope ◽  
Isotopic Substitution ◽  
Theoretical Evaluation ◽  
Theory And Experiment ◽  
Good Agreement

A theoretical analysis is made of the effect of nitrogen isotopic substitution on the rate of deammonation of phthalamide. Good agreement is found between theory and experiment.

Study on Free Oscillations of Systems with Even Nonlinearities by Means of the Method of Multiple Scales

2007 ◽  
Vol 10-12 ◽  
pp. 193-197
Author(s):  
J.M. Wen ◽  
Z.C. Cao
Keyword(s):  
Differential Equations ◽  
Multiple Scales ◽  
Method Of Multiple Scales ◽  
Nonlinear Differential Equations ◽  
Approximate Solutions ◽  
Free Oscillations ◽  
Analytical Technique ◽  
Spring System ◽  
Mass Spring ◽  
Good Agreement

An analytical technique, namely the method of multiple scales, is applied to solve the differential equations of free oscillations with even nonlinearities in a mass-spring system. Unlike other perturbation methods, the method of multiple scales is effective in determining the transient response as well as determining the approximation to the frequency of the nonlinear system. In this paper, the periodic solutions of the even nonlinear differential equations have been obtained by using the method of multiple scales. Compared with the numerical examples, the approximate solutions are in good agreement with exact solutions. The numerical and analytical solutions have clearly shown that there exists the so-called drift phenomenon in the free oscillations of systems with even nonlinearities without any external excitation.

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