Experimental study on a two-stage rolling piston CO2 compressor based on p–V indicator diagrams

2011 ◽  
Vol 226 (4) ◽  
pp. 995-1003 ◽  
Author(s):  
J Yang ◽  
Z Qi ◽  
J Chen ◽  
Z Chen
Keyword(s):  
Experimental Study ◽  
Operating Conditions ◽  
Test Rig ◽  
Two Stage ◽  
Second Stage ◽  
Compressor Inlet ◽  
Compressor Performance ◽  
Overall Efficiency ◽  
Rolling Piston ◽  
Discharge Pressure

In this article, a new two-stage rolling piston CO2 compressor was developed. A test rig was designed to measure the performance of this compressor. Based on the measured p–V indicator diagram, the distributions of indicated power and compressor performance under various operating conditions have been analysed in detail. It is shown that the discharge passage loss of the first stage and the suction passage loss of the second stage are much higher than other losses for the tested compressor. The overall efficiency of the tested compressor decreases by 1.2 per cent with the decrease of the discharge pressure at the same suction conditions. It is also found that the superheating at the compressor inlet has very small (0.3 per cent) effect on the compressor performance.

Experimental investigation on a two-stage CO2 compressor with high back pressure

2011 ◽  
Vol 226 (7) ◽  
pp. 1811-1820
Author(s):  
Zhaogang Qi ◽  
Jun Yang ◽  
Jiangping Chen ◽  
Haifeng Zhang ◽  
Li Zhang
Keyword(s):  
Compression Ratio ◽  
Piston Compressor ◽  
Back Pressure ◽  
Volumetric Efficiency ◽  
Mean Deviation ◽  
Two Stage ◽  
Second Stage ◽  
Two Samples ◽  
Rolling Piston ◽  
Discharge Pressure

In this article, two samples of two-stage rolling piston CO2 compressors with and without intercooler are developed and experimentally studied. These CO2 compressors are high back-pressure compressors, which mean the pressure inside compressor shell is the discharge pressure of the second stage. A test rig was designed to measure the performance and efficiency of this compressor. The test results show that the suction vapor temperature at the second stage inlet pipe has few influences on the performance and efficiency of the first compressor sample with intercooler. The volumetric efficiency linearly decreases with the increase of compression ratio of the suction and discharge pressure, and the volumetric efficiency can maintain in a relative constant range during a wide compression ratio changes in this high back-pressure design. There exists an optimum compression ratio for each suction pressure at the first stage, where the compressor isentropic efficiency is maximum. A generalized volumetric efficiency correlation for two-stage CO2 rolling piston compressor as a function of compression ratio is proposed and it can describe 100% of the test data within ±5.0% with a mean deviation of 1.7%. This would be helpful as a guide for designing such type compressor.

Supercritical Fluid Extraction of Polygonum cuspidatum and Subsequent Isolation by Simulated Moving Bed Chromatography

2013 ◽  
Vol 704 ◽  
pp. 18-30
Author(s):  
Ming Tsai Liang ◽  
Ru Chien Liang ◽  
Shu Qi Yu ◽  
Ri An Yan ◽  
Ku Yuan Liang
Keyword(s):  
Carbon Dioxide ◽  
Crude Extract ◽  
Operating Conditions ◽  
Effect Of Temperature ◽  
Simulated Moving Bed ◽  
Polygonum Cuspidatum ◽  
Two Stage ◽  
Moving Bed ◽  
Second Stage ◽  
Simulated Moving Bed Chromatography

In this work, supercritical carbon dioxide with ethanol as cosolvent was employed to extract bioactive compounds fromPolygonum Cuspidatum. Effect of temperature for 40 and 50 C on the extraction at 35 MPa was examined. It was found that extraction at 50 C resulted in high yield. A two-stage extraction at 50 C and 35 MPa was then designed to investigate effect of cosolvent on the recovery of resveratrol and emodin. The first stage extraction by solely using carbon dioxide can rarely extract resveratrol, but adding ethanol as cosolvent in the second stage significantly increases the extraction of resverarol and emodin. The crude extract obtained in the second stage was very stable against agglomeration and precipitation, because the first stage extraction helped to remove impurities from thePolygonum Cuspidatum. The stable crude extract was subsequently used as the feed for the SMB (simulated moving bed) separation. In this work, experimental validation was completed by solely using single SMB to isolate resveratrol, emodin, and physcion from the crude extract. As conducting the SMB experiments, the Triangle theory was used to help to determine the separable operating conditions. From the discussion of the experimental results, the criterion to obtain the pure resveratrol and physcion, and the concentrated emodin were depicted. Since both the extraction and the purification are conducted at low temperature, the bioactivity of the produced natural products will totally be preserved. The two-stage extraction and subsequent purification in this paper will provide greener and effective alternative for the development of botanical drugs.

scholarly journals Alternative Secondary Goals in Multiplicative Two-Stage Data Envelopment Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Chao Lu ◽  
Haifang Cheng
Keyword(s):  
Data Envelopment Analysis ◽  
Relative Efficiency ◽  
Data Envelopment ◽  
Nonparametric Method ◽  
Two Stage ◽  
Dea Model ◽  
Second Stage ◽  
China Construction Bank ◽  
Overall Efficiency ◽  
Decision Making Units

Data envelopment analysis (DEA) is a nonparametric method for evaluating the relative efficiency of a set of decision-making units (DMUs) with multiple inputs and outputs. As an extension of the DEA, a multiplicative two-stage DEA model has been widely used to measure the efficiencies of two-stage systems, where the first stage uses inputs to produce the outputs, and the second stage then uses the first-stage outputs as inputs to generate its own outputs. The main deficiency of the multiplicative two-stage DEA model is that the decomposition of the overall efficiency may not be unique because of the presence of alternate optima. To remove the problem of the flexible decomposition, in this paper, we maximize the sum of the two-stage efficiencies and simultaneously maximize the two-stage efficiencies as secondary goals in the multiplicative two-stage DEA model to select the decomposition of the overall efficiency from the flexible decompositions, respectively. The proposed models are applied to evaluate the performance of 10 branches of China Construction Bank, and the results are compared with the results of the existing models.

scholarly journals Research on Efficiency of Animation Enterprises Based on Two-Stage DEA Network System Model of Sharing Input Resources

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Shuo Zhang ◽  
Xuemei Yang ◽  
Jian Zhang ◽  
Mengjie Liao ◽  
Lin Qi
Keyword(s):  
Production Quality ◽  
System Model ◽  
Network System ◽  
Research Model ◽  
Two Stage ◽  
Second Stage ◽  
Production Quantity ◽  
Overall Efficiency ◽  
Stage Efficiency

This research constructs a two-stage DEA network system model of shared input resources to evaluate the efficiency of animation companies: the first-stage efficiency to reflect the production quantity and the second-stage efficiency to reflect the production quality of animation products, where the quality of animation products is judged based on the market recognition of the animation products. The overall efficiency in the research model is used to describe the development of animation enterprises. According to the result, it is concluded that the overall efficiency of the surveyed animation companies and the efficiency of each sub-stage have shown an upward trend, which is in line with the growth of the company's development.

Performance Measurements in Large and Small Scale Multi-Stage Axial Compressors

1997 ◽  
Author(s):  
Ulrich Waitke ◽  
Michael Ladwig
Keyword(s):  
Detailed Comparison ◽  
Operating Conditions ◽  
Small Scale ◽  
Scaling Effects ◽  
Performance Measurements ◽  
Test Rig ◽  
Design Data ◽  
Multi Stage ◽  
Compressor Performance ◽  
Stage Matching

During the commissioning of the prototype of the sequential combustion turbine GT24 extensive measurements of the compressor performance at design- and off-design-operation were accomplished besides the investigation of the other components of the GT. While the compressor performance at design operating conditions was as expected the data obtained showed some unexpected deviations from previously performed measurements of a 1/3-scale test rig of the low pressure compressor. This paper summarizes the results of the measurements and presents a detailed comparison between the measured performance of the GT compressor, the design data and the test rig. The discussion is focused on the influence of scaling effects on the aerodynamic performance and stage matching with particular emphasis on the Reynolds Number influence at different aerodynamic speeds. Furthermore some aspects of the starting behavior of the compressor are presented.

The 2-Stage Axial Turbine Test Facility “LISA”

2001 ◽  
Author(s):  
M. Sell ◽  
J. Schlienger ◽  
A. Pfau ◽  
M. Treiber ◽  
R. S. Abhari
Keyword(s):  
Unsteady Flow ◽  
Mass Flow ◽  
Measurement Techniques ◽  
Operating Conditions ◽  
Test Facility ◽  
Two Stage ◽  
Axial Turbine ◽  
Aerodynamic Pressure ◽  
Second Stage ◽  
The Impact

This paper describes the design and construction of a new two stage axial turbine test facility, christened “Lisa”. The research objective of the rig is to study the impact (relevance) of unsteady flow phenomena upon the aerodynamic performance, this being achieved through the use of systematic studies of parametric changes in the stage geometry and operating point. Noteworthy in the design of the rig is the use of a twin shaft arrangement to decouple the stages. The inner shaft carries the load from the first stage whilst the outer is used with an integral torque-meter to measure the loading upon the second stage alone. This gives an accurate measurement of the loading upon the aerodynamically representative second stage, which possesses the correct stage inlet conditions in comparison to the full two stage machine which has an unrealistic axial inlet flow at the first stator. A calibrated Venturi nozzle measures the mass flow at an accuracy of below 1%, from which stage efficiencies can be derived. The rig is arranged in a closed loop system. The turbine has a vertical arrangement and is connected through a gear box to a generator system that works as a brake to maintain the desired operating speed. The turbine exit is open to ambient pressure. The rig runs at a low pressure ratio of 1.5. The maximum Mach number at stator exit is 0.3 at an inlet pressure of 1.5 bar. The maximum mass flow is 14 kg/sec. Nominal rotor design speed is 3000 RPM. The tip to hub blade ratio is 1.29, and the nominal axial chord is 50 mm. The rig is designed to accommodate a broad range of measurement techniques, but with a strong emphasis upon unsteady flow methods, for example fast response aerodynamic pressure probes for time-resolved flow measurements. The first section of this paper describes the overall test facility hardware. This is followed by a detailed focus on the torque measurement device including stage efficiency measurements at operating conditions in Lisa. Discussion of measurement techniques completes the paper.

The Hemorrhagic Synchorne Complicating Extracorporeal Shunting of Blood: An Experimental Study of its Pathogenesis

1958 ◽  
Vol 02 (03/04) ◽  
pp. 218-225 ◽  
Author(s):  
George D. Penick ◽  
Hervy E. Averette ◽  
Richard M. Peters ◽  
Kenneth M. Brinkhous
Keyword(s):  
Experimental Study ◽  
Extracorporeal Circulation ◽  
Mechanical Damage ◽  
Fresh Blood ◽  
Two Stage ◽  
Second Stage ◽  
Severe Deficiency ◽  
Stored Blood ◽  
Antihemophilic Factor

SummaryDogs subjected to extracorporeal circulation with a modified D e Wall heart-lung apparatus developed thrombocytopenia and severe deficiency of the antihemophilic factor (AHF). To quantitate this reaction more accurately, a two-stage method of study was devised whereby citrated blood in the first stage was subjected to artificial, oxygenation and then in the second stage, was transfused into recipient dogs. In all cases, depression in AHF and platelets occurred even though fibrinogen remained at high levels. Depression in AHF levels could also be produced by mechanical damage to tissues of the extremities or by the autotransfusion of stored blood. Control transfusion of fresh blood produced no such effects.

scholarly journals Purification of biohydrogen from fermentation gas mixture using two-stage chemical absorption

2019 ◽  
Vol 90 ◽  
pp. 01012 ◽  
Author(s):  
Abdul Mum Nor Azira ◽  
Asli Umi Aisah
Keyword(s):  
Experimental Study ◽  
Hydrogen Gas ◽  
Wire Mesh ◽  
Biohydrogen Production ◽  
Future Application ◽  
Gas Mixture ◽  
Co2 Removal ◽  
Chemical Absorption ◽  
Two Stage ◽  
Second Stage

Research on biohydrogen production via fermentation process has shown a tremendous progress for the past few years. As biohydrogen production is being established, the purification of biohydrogen should consider the process flow for future application. This paper presents an experimental study of biohydrogen purification using two-stage chemical absorption. The research work focuses on carbon dioxide (CO2) removal, which is a major unwanted fermentation gas product via activated methyldiethanolamine (MDEA) and caustic (NaOH) in two-stage chemical absorption. The experiment was conducted at low pressure of 1 bar and normal room temperature of 29 °C using a ratio of 1:1 of CO2:H2 standard gas mixture as the feed. In the first stage, 40 wt. % MDEA was activated by using piperazine (PZ) with the concentration between 2 and 10 wt. %, whereas 20 wt. % NaOH was used in the second stage. It was found that 6 wt. % of PZ was required to fully activate 40 wt. % MDEA, which resulted in 79% CO2 removal. To improve CO2 removal, a gas distributor and wire mesh packed were used to create gas bubbles at higher geometrical surface. The experimental study successfully removed 99.59% of the total CO2, producing >99 mol% hydrogen gas purity from the second stage that used 20 wt. % NaOH.

Paper 3: An Analytical and Experimental Study of Self-Acting Valves in a Reciprocating Air Compressor

1969 ◽  
Vol 184 (18) ◽  
pp. 24-33 ◽  
Author(s):  
J. F. T. MacLaren ◽  
S. V. Kerr
Keyword(s):  
Mathematical Model ◽  
Experimental Study ◽  
Differential Equations ◽  
Digital Computer ◽  
Pressure Difference ◽  
Operating Conditions ◽  
Air Compressor ◽  
Ring Plate ◽  
Discharge Valve ◽  
Compressor Performance

A digital computer is used to solve the differential equations which form a mathematical model of a self-acting valve. The model describes the movement of a suction or a discharge valve, and the pressure difference across the valve. The computer results are compared with experimental records obtained over a range of operating conditions from a single-stage air compressor fitted with spring-loaded ring-plate valves. Subsequently the analysis provides conventional criteria of compressor performance.

Sign in / Sign up

Export Citation Format

Share Document