Compressor Parts Research Articles

Model and application of product conflict problem with integrated TRIZ and Extenics for low-carbon design

For lack of effective analysis methods, tools and model expression and management of conflict problems in modern product low-carbon design multi-conflict problem, low-carbon design conflict problem based on integrated TRIZ and Extenics is modeled. Firstly, an equivalent transformation model of conflict problem for low-carbon design is constructed and the core conflict factor is determined. Then the innovative solution to conflict problem for low-carbon design based on the TRIZ principle reasoning and formal extension transformation reasoning. In the end of the paper, a screw air compressor is taken as a low-carbon design case, and the conflict problem is focused on noise optimization and structural features of relevant parts of the screw air compressor. The performance data of the low-carbon design requirement is mapped into the muffler by conduction transformation. The case verified a good experimental result.

Ion-plasma nitriding as a method of instruments and parts durability

Improvement of the machines, parts, devices reliability as well as improvement of their quality and operation are topics of interest at the present time. Solution to these problems is related to hardening of the product surface layers in the first place. This article deals with parameters of nitriding process using the example of 38XM steel which is applied in essential parts of turbine installations and compressors operating at temperatures up to 400°C. The article also provides the results of nitriding at different modes.

Corrosion-resistant coating for GTE compressor parts made of steels with low tempering temperatures

The corrosion resistance of an Ni–Co–Cr–Al–Si–Y + SPh (SPh is silicophosphate impregnation) alloy coating on 30Kh13, 38Kh2MYuA, VKS5, and VKS7 structural steels with low tempering temperatures has been studied. The steel–coating compositions have been tested to determine the accelerated cyclic corrosion resistance, the corrosion resistance under tropic climate chamber conditions and in salt fog, the stress corrosion resistance, and the corrosion resistance in an industrial atmosphere. The heat stability of coated samples is studied, metallographic studies of the samples before and after the tests are performed, and the influence of the coating on the strength characteristics of the structural steels is studied.

Comparison of Cooling Different Parts in a High Pressure Ratio Centrifugal Compressor

Cooling in a centrifugal compressor can improve the performance and reduce the impeller temperature. In a centrifugal compressor, external walls can be cool down, which is known as the shell cooling. This method avoids undesirable effects induced by other cooling methods. Cooling can be applied on different external walls, such as the shroud, diffuser or the back plate. This paper focuses on seeking the most effective cooling place to increase the performance and reduce the impeller temperature. It is found that shroud cooling improves the compressor performance the most. Shroud cooling with 2400 W of cooling power increases the pressure ratio by 4.6% and efficiency by 1.49%. Each 500 W increase in the shroud cooling power, increases the efficiency by 0.3%. Diffuser cooling and back plate cooling have an identical effect on the polytropic efficiency. However, back plate cooling increases the pressure ratio more than diffuser cooling. Furthermore, only back plate cooling reduces the impeller temperature, and with 2400 W of cooling power, the impeller temperature reduces by 45 K.

Effect of Exit Pressure Pulsation on the Performance and Stability Limit of a Turbocharger Centrifugal Compressor

It is well known that compressor surge imposes a significant limit on the flow range of a turbocharged internal combustion engine. The centrifugal compressor is commonly placed upstream of the inlet manifold, and hence, it is exposed to the intermittent flow regime of the inlet valves. Surge phenomena have been well studied over the past decades, and there still remains limited information with regard to the unsteady impact caused by the inlet valves. This study presents an experimental evaluation of such a situation. Engine representative pulses are created by a downstream system comprising a large volume, two rotating valves, a throttle valve, and the corresponding pipe network. Different pulsation levels are characterized by means of their frequency and the corresponding amplitude at the compressor inlet. The stability limit of the system under study is evaluated with reference to the parameter B proposed by Greitzer (1976, “Surge and Rotating Stall in Axial Flow Compressors—Part II: Experimental Results and Comparison With Theory,” ASME J. Eng. Power, 98(2), pp. 199–211; 1976, “Surge and Rotating Stall in Axial Flow Compressors—Part I: Theoretical Compression System Model,” ASME J. Eng. Power, 98(2), pp. 190–198). B describes the dynamics of the compression system in terms of volume, area, equivalent length, and compressor tip speed as well as the Helmholtz frequency of the system. For a given compressor, as B goes beyond a critical value, the system will exhibit surge as the result of the flow instability progression. The reduced frequency analysis shows that the scroll diffuser operates in an unsteady regime, while the impeller is nearly quasi-steady. In the vicinity of the surge point, under a pulsating flow, the instantaneous operation of the compressor showed significant excursions into the unstable side of the surge line. Furthermore, it has been found that the presence of a volume in the system has the greatest effect on the surge margin of the compressor under the unsteady conditions.

New version of DEA compressor for a novel hybrid gas turbine cycle: TurboDEA

This study is aimed at introducing new version of DEA compressor and turboDEA, a novel gas turbine cycle that is specially configured to work by this compressor. This paper explains a preliminary study based on computer modeling for evaluating potential of the concept to heighten gas turbine technology. The paper is started by explaining mechanism of DEA compressor operation and its components, and is followed by designing a sample DEA compressor. Besides capability to adaptation to environmental elements, such a compressor potentially can operate with considerably less energy than conventional types. To show advantages of DEA compressor, performances of a sample turboDEA and its counterpart turbojet are calculated and compared. The comparison shows considerably low fuel consumption and higher flexibility of turboDEA beside turbojet. The study also presents performance sizing of the sample DEA compressor based on proper non-dimensional quantities, which shows its superior ability to adapt to environmental elements and user demands. Finally, cell actuator as the key part of DEA compressor is modeled and analyzed by ANSYS Multiphysics package.

The Analysis of the Model of Damping Mechanism for Shipborne Labyrinth Compressor Piston Components

Piston parts of a shipborne labyrinth compressor are mainly composed of a piston and a coated piston rod. In recent years, many studies have shown that the vibration response of coating structure is significantly reduced. Because of the non-contact of the piston, the cylinder case and guide support entirely depends on the piston rod. The lateral jitter can be regarded as the vibration of cantilever beam. However there is no effective method to separate the contribution of hard-coating damping from the damping of composite system. In this paper, based on separating the damping contribution of hard coating, the method of creating the damping mechanism model of piston rod is studied. Firstly, the piston rod before and after coating are tested and the characteristic parameters of vibration, such as natural frequency, damping ratio, vibration response are acquired. Moreover, according to the analysis of the storage and dissipation energy in the uncoated and coated rod, the damping contribution of hard coating has been confirmed. Finally, the Oberst beam theory is adopted to create the damping mechanism model of piston rod which includes both material damping and viscous damping. The correctness of analytical model is also verified by the experiment results.

Turbocharger flow computations with the Space–Time Isogeometric Analysis (ST-IGA)

Abstract We focus on turbocharger computational flow analysis with a method that possesses higher accuracy in spatial and temporal representations. In the method we have developed for this purpose, we use a combination of (i) the Space–Time Variational Multiscale (ST-VMS) method, which is a stabilized formulation that also serves as a turbulence model, (ii) the ST Slip Interface (ST-SI) method, which maintains high-resolution representation of the boundary layers near spinning solid surfaces by allowing in a consistent fashion slip at the interface between the mesh covering a spinning surface and the mesh covering the rest of the domain, and (iii) the Isogeometric Analysis (IGA), where we use NURBS basis functions in space and time. The basis functions are spatially higher-order in all representations, and temporally higher-order in representation of the solid-surface and mesh motions. The ST nature of the method gives us higher-order accuracy in the flow solver, and when combined with temporally higher-order basis functions, a more accurate representation of the surface motion, and a mesh motion consistent with that. The spatially higher-order basis functions give us again higher-order accuracy in the flow solver, a more accurate, in some parts exact, representation of the surface geometry, and better representation in evaluating the second-order spatial derivatives. Using NURBS basis functions with a complex geometry is not trivial, however, once we generate the mesh, the computational efficiency is substantially increased. We focus on the turbine part of a turbocharger, but our method can also be applied to the compressor part and thus can be extended to the full turbocharger.

Experimental study on variation of acoustical resonance frequency of duct with orifice depending on periodic motion

Abstract Recently, a linear compressor has been actively developed to improve the energy efficiency of home appliances, such as refrigerators. Unlike a reciprocating compressor, the suction part of a linear compressor is periodically moving. Therefore, the suction valve and the muffler constituting the suction part are periodically moving. However, up to now, there has been no research into the characteristics of the sound propagation in a periodically moving acoustic system. Thus, in this study, characteristics of sound propagation in a periodically moving acoustic system were investigated for the first time. Among a variety of acoustic filters used in a suction muffler, the change in the orifice impedance has been observed because this change is considered to be easily affected by periodically moving. Due to difficulty in measuring the orifice impedance in a periodically moving acoustic system, the change in the orifice impedance was predicted from the change in the input impedance of the suction muffler that included orifice. The experiments were carried out while changing the diameter and the pattern of orifice as well as length of the duct. As a result of experiments, the impedance of periodically moving orifice was changed depending on diameter, pattern of orifice and frequency band. Therefore, if periodically moving orifice was used to design a suction muffler in linear compressor or acoustic system, the change in the orifice impedance should be taken into consideration.

Heat pump without particle transport or external work on the medium achieved by differential thermostatting of the phase space.

We propose a mechanism that enables heat flow from a colder region to a hotter region without necessitating either particle transport or external work on the conductor, thereby bypassing the compressor part of a classical heat pump cycle. Our mechanism relies on thermostatting the kinetic and configurational temperatures of the same particle differently. We keep the two ends of a conductor, which in the present study is a single dimensional ϕ(4) chain, at the same kinetic temperature T(0), but at different configurational temperatures--one end hotter and the other end colder than T(0). While external energy is needed within the thermostatted regions to achieve this differential thermostatting, no external work is performed on the system itself. We show that the mechanism satisfies the statistical form of the second law of thermodynamics (the fluctuation theorem). The proposed mechanism reveals two interesting findings: (i) contrary to traditional thermodynamics where only the kinetic temperature is thought to govern heat conduction, configurational temperature can also play an important role, and (ii) the relative temperature difference between the kinetic and configurational variables governs the direction of heat flow. The challenge, however, is in developing experimental techniques to thermostat the kinetic and configurational variables of the same particle at different values.

Modeling of Partially Shrouded Impellers’ Effect on Operating Efficiency and Flow Range of Centrifugal Compressor

AbstractThe centrifugal impeller is one of the most critical aerodynamic parts of centrifugal compressors. The previous experimental investigation demonstrated that the fully shrouded impeller is b...

Improving Gas Cooling Technology at its Compression in the Booster Compressor Station

Improving the efficiency of gas air-cooling units of compressor stations requires consideration of a whole complex of varying parameters and appropriate regulation when there is decline in reservoir pressure and gas production volume in the fields. It determines the need to use two or more stages of compression, replaceable flow parts of gas compressors, new assembly available on the air coolers station. On the other hand, for many years of operation it is necessary to determine the optimum number of devices included in the cooling process, the total number of fans or a share of their total working load. The analysis shows the possibility of reducing energy consumption for fan drives which can reach 20-30%.

Hybrid coupling method to nonlinear acoustic source and linear duct system using parameter identification of the input impedance in fluid machinery

The acoustic source in fluid machinery is described as nonlinear. However, acoustic wave propagation in the muffler is represented by a linear system. Therefore, the acoustic source is modeled in the time domain, and the acoustic propagation is expressed in the frequency domain. The method of analyzing the acoustic in different domains is known as hybrid coupling. In this paper, a developed non-iterative hybrid coupling method was suggested, where the parameter identification using the rational fractional polynomial method is performed with the measured input impedance of the muffler described in the frequency domain. In this case, the relationship of the polynomial order of the denominator and numerator was determined from the analogy of a mechanical system. The approximated input impedance model is transformed to the state space model, which is described in the time domain. Finally, this model is coupled to a nonlinear acoustic source to analyze in the time domain. The proposed method can be used in more diverse condition than the other method. Simultaneously, a transient response can be obtained. The proposed method was experimentally verified using the suction part of a linear compressor, which is representative of fluid machinery.

Development of Energy Efficiency Design Map based on acoustic resonance frequency of suction muffler in compressor

Abstract The volumetric efficiency of the Internal Combustion (IC) engine and compressor can be increased by properly adjusting the acoustic resonance frequency of the suction muffler or the suction valve timing without any additional equipment or power source. This effect is known as acoustic supercharging. However, the energy efficiency has become more important than the volumetric efficiency because of the energy shortage issue and factors influencing consumers’ purchasing decisions. Therefore, methods for increasing the energy efficiency using the acoustic effect in the suction part of IC engine and compressor should be considered. In this study, a systematic method for improving the energy efficiency using the acoustic effect in the suction part of the compressor used in refrigerators and air conditioners was developed for the first time. This effect is named as the Acoustically Supercharged Energy Efficiency (ASEE). For the ASEE, first, a hybrid coupling method was suggested for the acoustical analysis in the suction part of the compressor. Next, an Energy Efficiency Design Map (EEDM) was proposed. This can serve as a design guide for suction mufflers in terms of the energy efficiency. Finally, sensitivity analyses of the Energy Efficiency Ratio (EER) and total massflow rate with respect to the acoustic pressure were conducted to identify the relationship between the acoustic pressure and the suction valve motion. This provides the physical background for the EEDM.

Investigation of the influence of plasma spray sealing coatings on the effect of sealing the TV2 - 117A turbojet engine compressor

This research shows the effect of the application of soft seals deposited by the atmospheric plasma spraying - APS process on the parts of the TV2-117A turbojet engine compressor. Western plasma spray technology and materials were applied for the first time on the parts of the compressor. The aim was to replace the existing sealant with a new class of materials in order to increase the sealing effect and provide air flow under the highest pressure through the compressor. Soft seals are formed as duplex systems consisting of the bonding underlayer based on NiCrAl and NiAl coatings and top sealing layer coatings based on Ni - 15% graphite, Ni - 25% graphite and AlSi - polyester. This paper presents the parameters for depositing the coatings on the compressor parts as well as the mechanical and microstructural characteristics of the coatings produced with the optimal deposition parameters. The mechanical properties of the coatings were assessed by testing the microhardness of the bonding layers using the HV0.3 method and the macrohardness of the sealing layers using the HR15W method. The tensile bond strength of the duplex coatings system was investigated by tensile testing. The microstructures of the coating layers were evaluated on an optical microscope - OM. The analysis of the microstructure of the deposited layers was performed in accordance with the Pratt & Whitney and TURBOMECA standards. Coating wear was determined from the change in the dimensions of the sealing surfaces before and after testing. The dimensions were measured in the coordinate measuring machine MAUSER ML 28. This paper presents the mean value of wear in milimeters and compares it with the values of the allowed tolerance in the compressor machined parts. The sealing effect of the compressor parts was tested on a TV2-117A engine at a test station and by flight tests on an Mi-8 (HT-40) helicopter. The tests have shown that the new system of sealing coatings increases the degree of efficiency of the compressor by 10% while reducing fuel consumption by 8%.

Investigation of Liquid-Steam Stream Compressor

Thermophysical model of liquid-steam stream compressor, results of analysis of experimental researches of boiling up streams of liquid in the broadening ducting and running part of liquid-steam stream compressor, description of forming of three critical modes of flow and structural inversion of stream are presented in this article. The mathematical model of working process which allows to determine parameters and characteristics of liquid-steam stream compressor is presented.

Recent Patents on Physical and Chemical Vapour Deposition for Static and Fatigue Corrosion Protection of Thin Coated Components

The use of Physical Vapor Deposition (PVD) and Chemical Vapor Deposition (CVD) thin coatings has become a widespread practice in the design of components subject to an aggressive environment. Corrosion in an aggressive environment can be critical for the design of structural components under constant and fatigue loads, due to the presence of Stress Corrosion Cracking (SCC) and fatigue corrosion. The protection from aggressive environments granted by the use of thin coatings is desired also in nonstructural, electrochemically active components, such as medical implants and fuel cells. In the present work, a review of the most recent industrial patents related to the application of PVD and CVD coatings developed in the last decade for the reduction of the detrimental effects of corrosion is presented. The article illustrates some selected patents which deal with the corrosion protection of components subject to fatigue loads and to static corrosion. Regarding dynamically loaded parts the reviewed papers describe thin coatings adopted to screen out turbine blades and disks from pitting corrosion, erosion and oxidation. A method to protect sliding parts of compressors using Hydrofluoroolefin refrigerant is also reported. In the latter part of the work, technical solutions for components under static corrosion are investigated, by presenting patents related to the coating of Implanted Medical Devices (IMD) and fuel cells, thus providing shielding from the external aggressive environment. Finally, a patent which proposes a multilayer finishing to improve the corrosion protection of common PVD treatments is presented. Keywords: Corrosion fatigue, erosion, fuel cells, implanted medical devices, oxidation, pitting corrosion, thin coatings, turbines.

Electrical Discharge Machining of AISI 329 Stainless Steel Using Copper and Brass Rotary Tubular Electrode

In the present study, the performance parameters of EDM process has been evaluated to achieve the feasibility in drilling of AISI 329 stainless steel which is extensively used in several industrial applications, e.g., heat exchangers, chemical tanks, pressure vessel parts, compressor parts, and seawater desalination plants. The selection of EDM control parameters largely depends on the material combination of electrode and work-piece. EDM manufactures only supply these control parameters for a limited number of material combinations. The present experimental work exhibits the optimum selection of control parameters (i.e., pulse current, pulse duration, pulse off time, and dielectric pressure) to maximize the material removal rate and minimize the electrode wear rate and taper angle of the hole simultaneously using hybrid optimization technique. The comparative investigation of copper and brass electrode revealed that copper electrode improves the hole quality and exhibits good machinability compare to brass electrode. It was observed that brass electrode wears rapidly because its high electrical resistivity, low melting point and low thermal conductivity compare to copper electrode. The most dominant parameters affecting the performance of EDM process has been evaluated using ANOVA. Further, the confirmation experiment shows a good agreement with the predicted value.

基于流体仿真的双螺杆压缩机的转子结构优化设计

我国国内的双螺杆压缩机型线设计水平相对于国外比较落后，转子型线是压缩机的重要零件，本文提出设计以新型圆弧包络线为基础的螺杆转子的新思路，以单边不对称摆线-销齿圆弧型线为研究对象，开发设计了新型转子型线。应用圆弧包络线构建了螺杆转子的齿廓线；利用三维软件建立了双螺杆压缩机原型线与新型线流场仿真模型，运用Fluent软件模拟了其在工作转速下压强与流速的分布规律。由仿真结果对新型线设计的合理性进行了预判，并为新型线的改进优化直至获得性能优良的双螺杆压缩机阴阳转子提供了参考依据。The level of designing the twin-screw compress or rotor profile in our country is relatively backward compared to foreign countries. The rotor is an important part of the screw compressor. This paper presents the new ideas based on arc-envelope to design the screw rotor. Taking the unilateral asymmetric cycloid-pins arc tooth profile as the research object, it designed a new type of rotor profile and built screw rotors with arc envelope tooth profile. It founded flow field simulation model of the original, and new twin-screw compressor rotor profile adopted the 3D software, simulated the distribution of its pressure and flow rate at operating speed with the software of Fluent. It predicted the rational of simulation results on the new designed rotor profile and provided a reference for the improvement of the new male and female twin-screw compressor rotors until getting the excellent performance rotors.

Numerical Control Machining of Scroll with Variable Thickness

With the development of scroll technology, the requirements of more efficient and more accurate processing method for scroll compressor parts become more urgent. This paper proposes a method to improve the machining effect of scroll compressor. The approach is based on 3-point arc approximation method which divides combined profile of scroll wrap into subparagraph arcs that can be interpolated on CNC System. This approach simplifies the programming process and improves the curve fitting effect. The results indicate that the fitting error is in the predetermined range, and the interpolation points of cutter center track are significantly less than those based on CAD/CAM software. The method presented in this paper is of significance to the NC machining of novel precise scroll profile.