Performance Of Screw Compressor Research Articles

Experimental Analysis of Twin Screw Compressor's Energetic Efficiency Depending on Volume Ratio

The current paper presents the results of the experimental analysis to assess and optimize the twin-screw compressor’s efficiency by varying the volume ratio. The experimental tests are conducted on the compressor's test bench, with a dedicated automation system inside the control console. The control and monitoring software allows parameter recording for subsequent visualization, data curation, and post-processing. The evaluation of screw compressor's performance requires a simultaneous analysis of the thermodynamic and flow processes, both of which depend on the compressor’s geometry. The obtained volumetric and adiabatic efficiencies are good, with values over 0.88 and 0.69, respectively.

Performance prediction and Bayesian optimization of screw compressors using Gaussian Process Regression

Optimizing the performance of screw compressors is critical for achieving high efficiency and reducing costs in various industrial and engineering applications. Often, the design and optimization processes are time-consuming owing to the underlying iterative complex analyses. In this context, the present research investigates the potential of Gaussian Process Regression (GPR) and Bayesian optimization for the prediction and optimization of the performance of an oil-flooded screw compressor. Specifically, the GPR-based surrogate model is developed to predict the compressor performance characteristics based on its four main geometrical design parameters such as wrap angle, relative length, tip speed of the male rotor and built-in volume ratio. The model is trained using a dataset comprising 19,200 data points relating the input design parameters with the compressor performance, obtained using physics-based multi-chamber thermodynamic models. While four different learning algorithms such as Support Vector Machine (SVM), Artificial Neural Network (ANN), Polynomial regression and GPR are explored, the GPR performed the best resulting in an R2 value of 0.99 for the test dataset after hyperparameter tuning. Further, the model is also experimentally validated on a completely unseen dataset, showing very good predictions with a maximum error of 5%. The resulting surrogate model is then used to optimize the compressor design parameters using Bayesian optimization. The results are compared with optimization using Genetic Algorithm (GA) and physics-based multi-chamber thermodynamic model. It was shown the proposed approach results in similar optimal design parameters but with a significantly less optimization time by a factor of 7. The study highlight the potential of machine learning-based prediction and optimization of screw compressors in engineering applications.

Experimental Investigation on the Effect of Water Cooling on a Dry Twin-Screw Air Compressor for Proton Exchange Membrane Fuel Cells

Due to the lack of oil injection cooling, it is usually necessary for dry twin-screw compressors to design cooling jackets to carry away the heat generated during operation. In order to investigate to what extent a cooling jacket can improve the performance of screw compressors, this study set up an experimental platform for a dry twin-screw compressor applied in fuel cell vehicles and used water as the working liquid in the cooling jacket. Then, the performance parameters of the screw compressor under different rotating speeds, discharge pressures, and cooling water flow rates were measured. It can be considered that the existence of a water cooling jacket is of great significance for improving the performance of dry screw compressors and improving extreme operating conditions. The research results may provide a reference for the development and improvement of dry twin-screw compressors in the future.

Experimental and numerical study on energy harvesting performance thermoelectric generator applied to a screw compressor

Abstract In this paper, an experimental and numerical investigation of thermoelectric generator for energy harvesting performance of screw compressors has been studied. The sources of heat recovery from compressors are recognized and a heat exchanger to mount the Thermoelectric Generator (TEG) module assembly is designed to adapt for implementation in this work. Computational fluid dynamics (CFD) is used to find out the temperature distribution in the heat exchanger and experimental work is carried out to validate CFD results. The heat exchangers, consisting of five TEG modules, temperature profile and voltage value have been studied numerically and experimentally. The parametric study has been studied to understand the influence of various system parameters on energy harvesting performance TEG based heat exchanger. An average of 1.6 V is generated by each TEG module and heat exchanger consists of five TEG and an average of 8 V is generated continuously by the heat exchanger. Also, it is proved that the usages of steel foam with 90 % porosity in heat exchanger improves the heat transfer rate and maximize the output from 8 V to 24 V in heat exchanger.

Application of Path Homotopy in Twin Screw Compressor Rotor Profile Design

This work explores application of an idea called ‘Path Homotopy’ from Topology in twin screw compressor rotor profile design. It is well known that twin screw rotor profiles impact the overall performance of screw compressors to a great extent. Almost all the well known profiles that are commercially used in twin screw compressors are generated out of analytical curves such as circles, lines and conic sections. Analytical representation has its own advantages in profile design but it limits the search space of all possible shapes that can be incorporated in profiles. This work aims at proposing an approach for rotor profiling that sticks to the analytical nature of curve representation in profiles while simultaneously extending the search space of curves that can be deployed in the design. Path homotopy has been identified as one of such approaches. Profile elements can be defined as homotopies between well known analytical curves (circles, lines and conic sections) and the homotopy parameter can directly influence these curves morphologically in their analytical form itself. In this way, shapes other than those used traditionally in profiling can be explored in search of the better rotor profiles.

Methods for regulating the performance of screw compressors

Methods for regulating the performance of screw compressors

Theoretical and experimental features of the thermodynamic process in oil injection screw compressors

For optimum performance of screw compressors, reduce wear and improve leakage, oil injection needs to be applied. The injected oil runs through the compressor together with the gas, taking a part of the heat of the gas resulting from compression during the process. The paper presents a theoretical analysis of the compression process affected by the cooling of the oil injection. The oil injection screw compressor is ideal for this process because the oil injected into the compressor along with the lubrication and sealing technology cools the compressed gas, which makes the compression process to be much closer to an isothermal process (minimum compression required). In order to calculate the thermodynamic of the gas lift process, the hydraulic calculation of the process, in which the extracted production, the amount of gas required, the injection pressures and the location of the valves, should be performed. These parameters were determined to correspond to the oil injection screw compressors manufactured in Romania by INCDT-COMOTI. The essential characteristics of those screw compressors that could be used considering the specificity of the location where the compressor will be mounted will be highlighted also.

Analysis on Performance of Screw Compressor in MVR system

Screw compressor is suitable for small scale mechanical vapor recompression (MVR) system especially for the solution with high boiling point elevation. In this paper, a mathematical model of screw compressor in MVR system is built and its working process is simulated. The results show that water injection improves the efficiency of screw compressor obviously and the compression process along saturated vapor line is realized if enough water is injected. The volumetric and isentropic efficiency is not sensitive with the water if more than flow rate of 35L/h is injected. The discharge temperature decreases from 133.4°C to 108°C with water quantities of 5L/h to 35L/h and then it is constant . The large saturated heat transfer difference in evaporator leads to decrement of volumetric efficiency but increment of isentropic efficiency. The mass flow rate of distilled water increase from 0.38t/h to 2.56 t/h and the saturated temperature difference increases from 4°C to 26.9°C when the rotating speed increases from 1000 rpm to 6000rpm.

Analysis of rolling bearing power loss models for twin screw oil injected compressor

The mechanical losses inside a screw compressor limit the performance of the compressor in terms of efficiency. These losses arise due to relative motion between elements inside the screw compressor. The estimation of mechanical losses predicted in the literature is around 10-15% of the total shaft power. One of the elements which contribute significantly to these losses is rolling element bearings. There are numerous mathematical models available which predict power losses in the rolling bearings.The objective of this paper is to study different models to predict power loss for rolling bearings and to predict the power losses for the bearings used for oil injected, twin screw compressor. A comparison between different power loss models for different operating conditions of compressor is also presented in this paper and results of analysis are compared with available experimental observations. The analysis helps to determine suitable power loss model for different operating conditions and more realistic predictions of the power losses. This allows designers for more accurate estimation of the performance of screw compressors.

Effect of oil-injection on twin screw compressor performance

Oil-injection improves twin-screw compressor performance significantly and its overall effect depends on the working fluid mass flow rate, the shaft speed, the injection position and the injected oil temperature. However, the individual contribution of each of these variables to the machine performance is yet not fully researched. Therefore, tests have been carried out on an air compressor with a male rotor diameter of 98mm, with injection nozzle sizes of 2, 3 and 4mm and with a nozzle of multiple holes. Tests were carried out with discharge pressures of 6.5, 8.5, 10.5 and 12.5 bar and rotor shaft speeds of 3000, 4000 and 5000 RPM. The results from the tests were compared with performance estimates at the same operating conditions as measurements against the standard injection nozzle of 5mm diameter. It was found that there is an optimum quantity of oil injected to obtain the best performance.

Experimental investigation of the water–injected process-gas screw compressor

The test rig for water-injected process-gas screw compressor is designed and established. The dry gas seal technology was adopted for the shaft seal of screw compressor and the test rig has the function of regulating and controlling the mass flow of injected water. The performance characteristics of process-gas screw compressor under different working conditions are investigated by experimental research. The effect of rotational speed, the injected water mass flow, and the discharge pressure on the performance of screw compressor including discharge temperature and power consumption were obtained. The experimental results show that the water injection could reduce the discharge temperature of compressor significantly and increase the capacity of screw compressor at the same time. There exists an optimum mass flow of injected water that could effectively reduce the discharge temperature and seal the clearance between the female and male rotor simultaneously. For the tested screw compressor prototype, the proper injected water-to-air mass ratio is about 2–3 L/m3. The additional power consumption caused by the injected water is small compared with the total shaft power. The established compressor test rig and the experimental results are helpful for the development and improvement on the performance of water-injected process-gas screw compressor.

A numerical method for evaluating effects of installation errors of grinding wheel on rotor profile in screw rotor grinding

The profile accuracy of screw rotor affects the performance of screw compressor directly. In precision form grinding, installation errors of grinding wheel are the crucial factors affecting profile accuracy of screw rotors. A numerical method for quantifying profile error of screw rotor was proposed to evaluate effects of installation errors of grinding wheel on rotor profile. Coordinate transformation and engagement theory were applied to generate rotor profile, and the error model of rotor profile was established by comparing the generated rotor profile with the original one. Furthermore, the error evaluation procedure was presented based on the discrete rotor profile points. Three kinds of installation errors of grinding wheel are analyzed including installation angle error, center distance error and axial position error in the numerical cases. By inputting installation errors of grinding wheel, the effects on rotor profile are evaluated considering both single-factor installation errors and coupled-factor installation errors of grinding wheel. The evaluated results provide a theoretical basis for error tracking and error compensation in screw rotor grinding. Grinding experiments were performed for female rotor with different installation errors. The experimental results verify the correctness of the evaluated results.

Potential to enhance performance of seawater-source heat pump by series operation

In this study, the performance enhancement potential by series operation in seawater-source heat pump system, assumed installed in Gangneung city near the East Sea in Korea, was investigated. An annual heating load for a typical Korean-style apartment house, which has an effective area of about 85 m2, was modeled by using TRNSYS program. An ambient condition was assumed to be in accordance with the Korean standard meteorological data, while the seawater temperature was calculated from the regression equation based on the measurement. A heat pump performance at full-load was calculated from the regression equation, which involves refrigerant's evaporating and condensing temperatures, based on a commercial screw compressor performance map. A part-load performance was also considered. Simulation results show that an annual heating performance of a seawater-source heat pump system can be improved by 8% or more by series operation under the simulation conditions considered in the present study.

Dynamic Performance Analysis of Submarine Screw Compressor Deballasting System

One dimensional dynamic model for submarine low pressure screw compressor deballasting system performance analysis is developed. Cross section of outer shell of ballast tank is described as cylinder, one dimensional flow equations combined with screw compressor performance model are employed to describe compressors flow characteristic. Coupled effect between gas pressure in ballast tank and discharging performance of screw compressor is considered in the presenting model as gas leakage during compressing process is taken into account. Deballasting duration for one certain submarine model is calculated using the developed model, and the result agrees well with that obtained by using Chinese state code for submarine low pressure system design. For different cross section tank models as circular section model, parabolic section model and trapezoidal section model, dynamic performance of screw compressor deballasting system is studied using the validated model. Gas pressure in tank, dropping speed of tank water surface and draft of submarine are simulated, and the results show that little difference of deballasting duration is caused by changing tank cross section. The most stable deballasting process is achieved by using a circular section tank. Deballsting performance is also studied as tonnage of submarine and volume of ballast tank change and commonsense conclusions are obtained.

PERFORMANCE OF OIL-INJECTED TWIN-ROTORS SCREW COMPRESSOR

In order to improve the performance of screw compressor, it is important to know, understand, and analysis the different geometrical as well as operating parameters on the compressor performance. Consequently, the present study is concerned with obtaining the characteristics of twin-screw compressor by using a simulation code named SCORPATH. Explanation of the code is presented and discussed. A parametric study was performed to determine the effect of the geometrical and the operating parameters on the performance of screw compressor. The study revealed that the geometrical parameters: clearance gap, number of lobes in the rotors, rotor relative length, and screw wrap angle, have significant effect on the performance of the screw compressor. In addition, built in volume ratio, tip speed, suction and discharge pressures, are the operating parameters which have a great effect on the performance of the twin-screw compressor.

Study of Liquefaction Characteristics of a Helium Liquefier using Claude Cycle.

The authors are now developing a helium liquefier of l00 1/h liquefaction capacity for use with a 70 MW superconducting generator. This paper describes liquefaction characteristics of a helium liquefier using various types of Claude cycle with multitude expanders arranged in parallel. The calculation method for liquefaction characteristics was established and the liquefaction capacity and FOM based on the actual screw compressor performance were calculated and shown in figures with several expansion methods for liquefaction combined with various precooling procedures. From these results, the optimized conditions for various Claude cycles were clarified for the best FOM and the greatest liquefaction capacity.

Performance of Screw Compressor for Small-Capacity Helium Refrigerators

Performance of Screw Compressor for Small-Capacity Helium Refrigerators

Analysis of screw compressor performance. 3rd report Calculation of performance of several sample rotors.

Analysis of screw compressor performance. 3rd report Calculation of performance of several sample rotors.

Analysis of Screw Compressor Performance : 1st Report, Calculation of Geometrical Characteristics

スクリュ圧縮機の溝容積やシールライン長さ等の幾何学的特性値を解析した。仮想仕事の原理を応用して溝容積をシールラインから直接求める等、電算機での計算に便利な独自の手法を導入した。種々のサンプルロータについて計算の結果、歯数の多いロータは、吐出しポート面積が大きいが、シールラインが長いこと、全巻き角の大きいロータは吐出しポート面積が大きく、ブローホール面積が小さいこと等がわかった。