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Numerical Simulation Of Wrap Scroll Temperature For Refrigeration And Air Conditioning Compressors, Jordi Rovira, Joaquim Rigola, Carlos D. Pérez-Segarra, Assensi Oliva Jul 2012

Numerical Simulation Of Wrap Scroll Temperature For Refrigeration And Air Conditioning Compressors, Jordi Rovira, Joaquim Rigola, Carlos D. Pérez-Segarra, Assensi Oliva

International Compressor Engineering Conference

Being part of a model which simulates the whole consecutive overall compression process in a scroll compressor by solving equations of mass, momentum and energy balance for fluid refrigerant (Rovira et al.,2006), an updated version is presented. In this new model, an energy balance over the scroll wraps is implemented; where temperatures and heat fluxes are obtained dividing the wall into 36 parts (slices) each turn. The scroll wrap is divided into different solid slices; energy balance is carried out, taking into account: i) conduction along the scroll wrap; ii) convection heat transfer between each slice and each fluid chamber, …

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A Procedure To Optimize Reed Type Valves Considering Efficiency And Bending Fatigue, Ernane Silva, Cesar J. Deschamps, Eduardo A. Fancello Jul 2012

A Procedure To Optimize Reed Type Valves Considering Efficiency And Bending Fatigue, Ernane Silva, Cesar J. Deschamps, Eduardo A. Fancello

International Compressor Engineering Conference

Reed valves are the most common type of valves used in small compressors due to their simplicity and low cost. Such valves greatly affect the compressor volumetric and isentropic efficiencies and their suitable design is also crucial for reliability, since they may be subjected to severe bending and impact stresses. This paper reports an optimization procedure for reed type valves considering efficiency and bending fatigue, which is attained by coupling a thermodynamic model for the compression cycle and a finite element model for the valve dynamics. Then, a genetic algorithm is adopted to find different valve geometries that give the …

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Modeling Of Gas Leakage Through Compressor Valves, Leandro R. Silva, Cesar J. Deschamps Jul 2012

Modeling Of Gas Leakage Through Compressor Valves, Leandro R. Silva, Cesar J. Deschamps

International Compressor Engineering Conference

Gas leakage in the incomplete sealing of valves may significantly affect the volumetric and isentropic efficiencies of compressors. This paper describes a model developed to predict gas leakage in reed type valves of small reciprocating compressors commonly adopted for household refrigeration. Computations are carried out for a wide range of pressure differences that prevail in the valve clearances during the complete compression cycle. Results for mass flow rate in the suction and discharge valves are used to analyze the influence of geometric parameters on the leakage process. Reed deflection into the valve port due to pressure load is seen to …

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Derivation Of Optimal Scroll Compressor Wrap For Minimization Of Leakage Losses, Ian H. Bell, Eckhard A. Groll, James E. Braun, W. Travis Horton Jul 2012

Derivation Of Optimal Scroll Compressor Wrap For Minimization Of Leakage Losses, Ian H. Bell, Eckhard A. Groll, James E. Braun, W. Travis Horton

International Compressor Engineering Conference

The scroll wraps of a scroll compressor play a very important role in the compressor’s efficiency due to their impact on leakage and leakage irreversibilities. In this work, a short summary of the scroll compressor geometry is presented. Using the geometry of the scroll wraps, an optimal scroll wrap geometry is derived for a given set of constraints on compressor displacement, scroll wrap thickness and volume ratio. This optimal scroll wrap geometry can be used as a starting point for further optimization in a detailed compressor model that includes the effects of mechanical losses.

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Simulation Analysis Of A Two Rolling Piston Expander Replacing Throttling Valve In Conventional Refrigerant Heat Pump System, Li Zhao, Minxia Li, Yitai Ma, Zhongyan Liu Jul 2012

Simulation Analysis Of A Two Rolling Piston Expander Replacing Throttling Valve In Conventional Refrigerant Heat Pump System, Li Zhao, Minxia Li, Yitai Ma, Zhongyan Liu

International Compressor Engineering Conference

An expander is employed to replace a throttling valve in a heat pump system of the conventionorder to further improve the efficiency of the system by recovering partial expansion work to decconsume of the system. Due to large expansion ratios of conventional refrigerants, a twone-stage expander was proposed and designed. Simulation analysis was developed by analyzing irreversible losses in the expansion work process. The simulation results show that, friction losses of a conventional refrigerant expander are 80.2% of total losses, which are the main factors to influence the efficiency of expander. Then the measures of reduciong friction losses are presented, …

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The Application Of Monte Carlo Method For Sensitivity Analysis Of Compressor Components, Marcos Giovani Dropa De Bortoli, Julio César Silva Jul 2012

The Application Of Monte Carlo Method For Sensitivity Analysis Of Compressor Components, Marcos Giovani Dropa De Bortoli, Julio César Silva

International Compressor Engineering Conference

The robustness evaluation of compressor components must take into account the variations in the mechanical properties of the material (such as Young's modulus and mass density), geometric parameters (as radius, thickness, length) and loads. Sometimes, the combination of these factors could result in the component failure. The correct way to assess the robustness of the component (considering the parameters variation) is through the statistical analysis using probabilistic design techniques. One methodology is the application of Monte Carlo method to generate random combinations of geometrical, loads and physical parameters that produce the same real component variation. This work shows the application …

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Multivariable Identification And Control Of A Calorimeter Used For Performance Evaluation Of Refrigerant Compressors, Rodolfo C. C. Flesch, Julio E. Normey Rico, Carlos A. Flesch, André P. Rosa Jul 2012

Multivariable Identification And Control Of A Calorimeter Used For Performance Evaluation Of Refrigerant Compressors, Rodolfo C. C. Flesch, Julio E. Normey Rico, Carlos A. Flesch, André P. Rosa

International Compressor Engineering Conference

Refrigerant compressors are relatively complex products that require a wide variety of tests to be performed for both product development and quality control. Performance tests are an example of such tests and they are typically performed using test rigs with calorimeters. This paper presents the experimental results of the use of a multivariable dead-time compensating structure to control the conditions at the calorimeter inlet and outlet. Besides the control results themselves, the paper presents the identification of the multivariable model used for control purposes, as well as it discusses tuning and implementation of the proposed controller. The closed-loop experimental results …

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The Research On The Performance Of Oil-Gas Cyclone Separators In Oil Injected Compressor Systems With Considering The Collision And Breakup Of Oil Droplets, Xiang Gao, Yaopeng Zhao, Xin Yang, Yunfeng Chang, Xueyuan Peng Jul 2012

The Research On The Performance Of Oil-Gas Cyclone Separators In Oil Injected Compressor Systems With Considering The Collision And Breakup Of Oil Droplets, Xiang Gao, Yaopeng Zhao, Xin Yang, Yunfeng Chang, Xueyuan Peng

International Compressor Engineering Conference

The high-speed swirling flow field in the cyclone oil-gas separator will cause the breakup of oil droplets, thus reducing the separation efficiency. In this paper, the performance of an oil-gas cyclone separator was investigated through both numerical simulations and experiments with considering the breakup of oil droplets in oil-gas cyclone separators. The gas flow field was simulated using the RSM turbulence model and the trajectory of the oil droplets was calculated by the Discrete Phase Model(DPM).The breakup of oil droplets was simulated by TAB model and the wall boundary of oil droplets was treated as Reflect boundary. Meanwhile, the separation …

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Sound Attenuation In Elliptic Mufflers Using A Regular Perturbation Method, Subhabrata Banerjee, Anthony M. Jacobi Jul 2012

Sound Attenuation In Elliptic Mufflers Using A Regular Perturbation Method, Subhabrata Banerjee, Anthony M. Jacobi

International Compressor Engineering Conference

The study of sound attenuation in an elliptical chamber involves the solution of the Helmholtz equation in elliptic coordinate systems. The Eigen solutions for such problems involve the Mathieu and the modified Mathieu functions. The computation of such functions poses considerable challenge. An alternative method to solve such problems had been proposed in this paper. The elliptical cross-section of the muffler has been treated as a perturbed circle, enabling the use of a regular perturbation approach to solve the wave equation. The Eigen vectors of the perturbed system has been approximated by a series summation of the unperturbed Eigen solutions. …

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Numerical Analysis Of Performance, Rotor Temperature Distributions, And Rotor Thermal Deformation Of An R134a Screw Compressor, Shenghung Hsieh, Wenhsin Hsieh, Chishun Huang, Yuhua Huang Jul 2012

Numerical Analysis Of Performance, Rotor Temperature Distributions, And Rotor Thermal Deformation Of An R134a Screw Compressor, Shenghung Hsieh, Wenhsin Hsieh, Chishun Huang, Yuhua Huang

International Compressor Engineering Conference

A numerical analysis is performed to systematically calculate the performance, rotor temperature distributions, and rotor thermal deformation of an R134a screw compressor. The analysis procedure includes three major steps. The first step calculates the efficiencies and the temperature- and pressure-time histories of the refrigerant during a compression cycle of the screw compressor. The calculation is performed based on a theoretical model, which considers the mass and energy conservation laws, the leakages through various paths, and the discharges of gas and oil. The heat transfer between gas and oil is also considered. The second step calculates the temperature distributions in the …

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Comparison Of The Sound Quality Characteristics For The Outdoor Unit According To The Compressor Model., Sang-Gil Park, Jeong-Taek Park, Ki-Won Seo, Gil-Bong Lee Jul 2012

Comparison Of The Sound Quality Characteristics For The Outdoor Unit According To The Compressor Model., Sang-Gil Park, Jeong-Taek Park, Ki-Won Seo, Gil-Bong Lee

International Compressor Engineering Conference

As for the criteria to purchase an air conditioner, noise level has emerged as an important issue, equal to design characteristics and performance. The main feature of the noise of the outdoor unit is a complex characteristic noise due to the operation of the fan and compressor. Air-borne noise is usually caused by the vortex separation on the fan blade, and structure-borne noise is caused by compressor or vibration transmission to the chassis and components. Due to the efforts of researchers and designers who have worked on noise reduction, the sound pressure level (SPL) of outdoor units launched on the …

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Some Aspects Of Estimating Geometric Characteristics Of Screw Compressors, David Buckney, Ahmed Kovacevic, Elvedin Mujic, Nikola Stosic Jul 2012

Some Aspects Of Estimating Geometric Characteristics Of Screw Compressors, David Buckney, Ahmed Kovacevic, Elvedin Mujic, Nikola Stosic

International Compressor Engineering Conference

The methods used today for the calculation of screw compressor thermodynamic and fluid flow processes, from quasi one-dimensional thermodynamic models to three-dimensional computational fluid dynamics (CFD) procedures, require accurate identification and quantification of geometric parameters, such as volume, gradient and cross-section, leakage flow and blow-hole areas. Historically, some of the geometric characteristics have been neglected, or approximated when calculation accuracy was not essential. However, more sophisticated models may lose some of their advantages if accurate geometric characteristics are not included in them. The work presented in this paper is aimed to enhance the accuracy of geometric calculations. The usual geometric …

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Calculated Optimal Mechanical Efficiency Of A Large Capacity Reciprocating Compressor, Takuma Tsuji, Tatsuya Oku, Noriaki Ishii, Keiko Anami, Charles W. Knisely Jul 2012

Calculated Optimal Mechanical Efficiency Of A Large Capacity Reciprocating Compressor, Takuma Tsuji, Tatsuya Oku, Noriaki Ishii, Keiko Anami, Charles W. Knisely

International Compressor Engineering Conference

In this study, calculations of the mechanical efficiency of a large reciprocating compressor, developed by Mayekawa MFG. Co., Ltd., with a per cylinder suction volume of 1300 cm3 were carried out. These calculations were used to confirm whether the empirical combination of major design parameters in the Mayekawa compressor delivers optimal mechanical efficiency. Initially, the theoretical equation of motion of the rotating crankshaft is developed. Subsequently, computer calculations are carried out to determine the mechanical efficiency for various combinations of the major design parameters for operating speeds of 800, 1000 and 1200 rpm. From these calculations, the optimal combination parameters …

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Thermodynamic Design Of Screw Motors For Constant Waste Heat Flow At Medium Temperature Level, Jan Hütker, Andreas Brümmer Jul 2012

Thermodynamic Design Of Screw Motors For Constant Waste Heat Flow At Medium Temperature Level, Jan Hütker, Andreas Brümmer

International Compressor Engineering Conference

This paper focuses on the interaction of the geometric parameters of screw motors and the fluid parameters of the system in compliance with the boundary condition of constant waste heat flow. Within the thermodynamic simulation the systematic variation of the geometric machine parameters include the number of lobes on male and female rotor and the internal volume ratio. The variation range of the system parameters consists of the dependent parameters of temperature and mass flow and of the pressure on the high pressure side of the machine. The conclusive assessment of the energetic efficiency and the operating behavior of the …

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Numerical Evaluation Of Performance Curves Of A High Frequency Microcompressor, Celso Kenzo Takemori, Fabian Fagotti Jul 2012

Numerical Evaluation Of Performance Curves Of A High Frequency Microcompressor, Celso Kenzo Takemori, Fabian Fagotti

International Compressor Engineering Conference

This work presents a methodology for the numerical simulation of reed valves of a small-size reciprocating compressor (approximately 200 mm in length, 60 mm in diameter), oil free and operating at high frequency. A fluidstructure interaction methodology is employed, where the fluid domain is modeled by the tridimensional transient Navier-Stokes equations, while the solid domain is governed by a beam model considering geometrical contacts between valves and stoppers (valve plate, piston, etc.) Results are shown for mass flow, pump power consumption and valve losses for evaporating temperatures ranging from -15 degrees Celsius to +40 degrees Celsius, and condensing temperatures from …

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Numerical Study On Rotor Deformation Of Multiphase Twin-Screw Pumps Under High Gas Volume Fraction Conditions, Bin Hu, Feng Cao, Ziwen Xing Jul 2012

Numerical Study On Rotor Deformation Of Multiphase Twin-Screw Pumps Under High Gas Volume Fraction Conditions, Bin Hu, Feng Cao, Ziwen Xing

International Compressor Engineering Conference

Multiphase pumping with twin-screw pumps is a relatively new technology that has been proven successful in a variety of field applications. It has three advantages such as less environment pollution, few separation equipments and more convenient operation than the conventional system. Despite many advantages of this technology, some problems have been encountered when operating under conditions with high gas volume fractions (GVF). While twin-screw multiphase pump is operating under high GVF conditions, the inner temperature of the pump increases obviously. The clearances between rotors change greatly and influence the volumetric efficiency of the twin-screw multiphase pumps. In some severe conditions, …

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Acoustic Calculation With The Free Solver Code_Aster, David Leray, Yvon Goth Jul 2012

Acoustic Calculation With The Free Solver Code_Aster, David Leray, Yvon Goth

International Compressor Engineering Conference

The aim of this article is to share our experience in compressor acoustic calculation using the free solver Code_Aster. We will review some typical compressor noise problem, how we modelize them and some results examples. Muffler transmission loss with different acoustic termination, acoustic field inside compressor cavity and rigid body motion of the shell, compressor shell acoustic radiation are some of the case study discussed in this article. Code_Aster is a free and powerful solver developed by EDF, the French electricity company. It is an attractive solution for all company that cannot afford the cost of a commercial acoustic code.

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Modeling Of A Novel Spool Compressor With Multiple Injection Ports, Margaret M. Mathison, James E. Braun, Eckhard A. Groll Jul 2012

Modeling Of A Novel Spool Compressor With Multiple Injection Ports, Margaret M. Mathison, James E. Braun, Eckhard A. Groll

International Compressor Engineering Conference

While models have previously been developed to investigate scroll compressor performance with a single injection port, the model described in this paper explores the effect of multiple injection ports on the performance of a novel rotary spool compressor. The model includes the effects of heat transfer and leakage and is numerically solved to predict the compressor power consumption and mass flow rate. The injection ports are modeled assuming that saturated vapor is injected at a specified pressure and the timing of the injection process can be controlled. Running at a speed of 1907 rpm with R-22 as the working fluid, …

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R32 Scroll Compressors Technology, Hongling Xu, Chao Yan, Stéphane Watts, Pierre Ginies Jul 2012

R32 Scroll Compressors Technology, Hongling Xu, Chao Yan, Stéphane Watts, Pierre Ginies

International Compressor Engineering Conference

The purpose of the work is to describe technology used to design a scroll compressor with R32 refrigerant. Study what are the main differences and their implications compared to R410A refrigerant scroll compressors. And also study from mechanical scroll compressor design point of view up to its system integration, what are the main design changes taken in account R32 properties, what are the main options to handle high discharge refrigerant temperature, what are the advantages and consequences of each options, what solution will be chosen.

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Topology Optimization Of Suction Muffler For Noise Attenuation, Jin Woo Lee, Dong Wook Choi Jul 2012

Topology Optimization Of Suction Muffler For Noise Attenuation, Jin Woo Lee, Dong Wook Choi

International Compressor Engineering Conference

A topology optimization method is developed to optimally design suction mufflers in reciprocating compressors. Suction mufflers should be designed for high noise reduction. The suction mufflers are not easy to systematically design because their outer shape is so complicated and the center axes of the inlet/outlet do not coincide. Muffler researchers in industry have designed the internal configuration of suction mufflers intuitively and experientially. However, since our proposed muffler design method is not restricted to location of the inlet and outlet and to the outer shape of suction muffler, it could be applied to suction muffler design problems. A topology …

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Iso 16363: Trustworthy Digital Repository Certification In Practice, Michael Witt, Matthew Kroll, David Minor, Bernie Reilly Jul 2012

Iso 16363: Trustworthy Digital Repository Certification In Practice, Michael Witt, Matthew Kroll, David Minor, Bernie Reilly

Libraries Faculty and Staff Presentations

Three perspectives are presented from the United States on the new ISO 16363 certification process from a repository that is currently preparing to undergo an audit (Purdue University), a repository that has recently been certified as a trustworthy digital repository (Chronopolis Digital Preservation Network, University of California, San Diego), and an auditor (Center for Research Libraries). After a concise overview of the certification process, each panelist will offer insights and practical tips based on their experience and participate in a moderated discussion that includes questions and comments from the audience.

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Unh Tree Walk Podcast Offers Fresh View Of Campus, Carrie Sherman Jul 2012

Unh Tree Walk Podcast Offers Fresh View Of Campus, Carrie Sherman

UNH Today Archive

No abstract provided.

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Unh, Michigan Aerospace Corp To Bring Radiation Detector To Market, David Sims Jul 2012

Unh, Michigan Aerospace Corp To Bring Radiation Detector To Market, David Sims

UNH Today Archive

No abstract provided.

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Unh Partners With City Year New Hampshire, Lori Wright Jul 2012

Unh Partners With City Year New Hampshire, Lori Wright

UNH Today Archive

No abstract provided.

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Calling All Prospective Csis: Unh Offers New Program In Forensics, Lori Wright Jul 2012

Calling All Prospective Csis: Unh Offers New Program In Forensics, Lori Wright

UNH Today Archive

No abstract provided.

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Tall Ships, Unh Communications And Public Affairs Jul 2012

Tall Ships, Unh Communications And Public Affairs

UNH Today Archive

No abstract provided.

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Lerajjarenra-O-Kel-Ly V. Jones Respondent's Brief Dckt. 39048 Jul 2012

Lerajjarenra-O-Kel-Ly V. Jones Respondent's Brief Dckt. 39048

Not Reported

No abstract provided.

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Emissions Calculated From Particulate Matter And Gaseous Ammonia Measurements From Commercial Dairy In California, Usa, Kori D. Moore, Christian C. Marchant, Emyrei Young, Randal S. Martin, Richard L. Pfeiffer, John H. Prueger, Jerry L. Hatfield Jul 2012

Emissions Calculated From Particulate Matter And Gaseous Ammonia Measurements From Commercial Dairy In California, Usa, Kori D. Moore, Christian C. Marchant, Emyrei Young, Randal S. Martin, Richard L. Pfeiffer, John H. Prueger, Jerry L. Hatfield

Space Dynamics Laboratory Publications

Emission rates and factors for particulate matter (PM) and gaseous ammonia (NH3) were estimated from measurements taken at a dairy in June 2008. Concentration measurements were made using both point and remote sensors. Filter-based PM samplers and optical particle counters (OPCs) characterized aerodynamic and optical properties, while a scanning elastic lidar measured particles around the facility. The lidar was calibrated to PM concentration using the point measurements. NH3 concentrations were measured using 23 passive samplers and 2 open-path Fourier transform infrared spectrometers (FTS). Emission rates and factors were estimated through both an inverse modeling technique using AERMOD coupled with measurements …

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Aglite: A 3-Wavelength Lidar System For Quantitative Assessment Of Agricultural Air Quality And Whole Facility Emissions, Michael D. Wojcik, Kori D. Moore, Jerry L. Hatfield, Richard L. Pfeiffer, John H. Prueger, Randal S. Martin Jul 2012

Aglite: A 3-Wavelength Lidar System For Quantitative Assessment Of Agricultural Air Quality And Whole Facility Emissions, Michael D. Wojcik, Kori D. Moore, Jerry L. Hatfield, Richard L. Pfeiffer, John H. Prueger, Randal S. Martin

Space Dynamics Laboratory Publications

Ground based remote sensing technologies such as scanning lidar systems (light detection and ranging) are increasingly being used to characterize ambient aerosols due to key advantages (i.e., wide area of regard (10 km2), fast response time (s-1), high spatial resolution (<10 >m) and high sensitivity). Scanning lidar allows for 3D imaging of atmospheric motion and aerosol variability, which can be used to quantitatively evaluate particulate matter (PM) concentrations and emissions. Space Dynamics Laboratory, in conjunction with USDA ARS, has developed and successfully deployed a lidar system called Aglite to characterize PM in diverse settings. Aglite is a portable scanning elastic …

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Ionospheric Signatures Of Tohoku-Oki Tsunami Of March 11, 2011: Model Comparisons Near The Epicenter, David A. Galvan, Attila Komjathy, Michael P. Hickey, Philip Stephens, Jonathan Snively, Y. Tony Song, Mark D. Butala, Anthony J. Mannucci Jul 2012

Ionospheric Signatures Of Tohoku-Oki Tsunami Of March 11, 2011: Model Comparisons Near The Epicenter, David A. Galvan, Attila Komjathy, Michael P. Hickey, Philip Stephens, Jonathan Snively, Y. Tony Song, Mark D. Butala, Anthony J. Mannucci

Publications

We observe ionospheric perturbations caused by the Tohoku earthquake and tsunami of March 11, 2011. Perturbations near the epicenter were found in measurements of ionospheric total electron content (TEC) from 1198 GPS receivers in the Japanese GEONET network. For the first time for this event, we compare these observations with the estimated magnitude and speed of a tsunami-driven atmospheric gravity wave, using an atmosphere-ionosphere-coupling model and a tsunami model of sea-surface height, respectively. Traveling ionospheric disturbances (TIDs) were observed moving away from the epicenter at approximate speeds of 3400 m/s, 1000 m/s and 200–300 m/s, consistent with Rayleigh waves, acoustic …

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