scholarly journals Three Approaches to Low-Duty Turbo Compressor Efficiency Exploitation Evaluation

2020 ◽  
Vol 10 (10) ◽  
pp. 3373
Author(s):  
Igor Poljak ◽  
Ivica Glavan ◽  
Josip Orović ◽  
Vedran Mrzljak
Keyword(s):  
Operating Regime ◽  
Boiler Load ◽  
Energy And Exergy ◽  
Compressor Performance ◽  
Turbo Compressor ◽  
Liquid Natural Gas ◽  
Compressor Efficiency ◽  
Operating Regimes ◽  
Isentropic Efficiency ◽  
Diagram Techniques

This paper presents three approaches for isentropic, energy, and exergy evaluations of a low-duty liquid natural gas (LNG) vapor turbo compressor during exploitation on a conventional LNG carrier. The evaluation was conducted on the measured performance parameters under 22 various turbo compressor operating regimes. The turbo compressor performance was evaluated in the temperature span from −69 to −105 °C and during changes in the rpm of the main propulsion turbine and, consequently, the main boiler load. The results show that the highest measured turbo compressor isentropic efficiency is in agreement with the manufacturer specifications, equaling 75.23% at a main propulsion turbine rpm of 53.5. At the highest measured loads and rpm, the turbo compressor energy and exergy efficiencies reach the highest values of 57.81% and 28.51%, respectively. In each observed operating regime, the influence of the ambient temperature change on the turbo compressor exergy efficiency was investigated. At the lowest and the highest measured loads, turbo compressor energy and exergy flow streams are presented in a Sankey diagram. Techniques for cargo temperature maintenance during the ship voyage are presented, as the results show that low suction gas temperatures influence turbo compressor efficiency.

scholarly journals Energy and Exergy Evaluation of a Two-Stage Axial Vapour Compressor on the LNG Carrier

Entropy ◽  
2020 ◽  
Vol 22 (1) ◽  
pp. 115 ◽  
Author(s):  
Igor Poljak ◽  
Josip Orović ◽  
Vedran Mrzljak ◽  
Dean Bernečić
Keyword(s):  
Average Energy ◽  
Exergy Efficiency ◽  
Dual Fuel ◽  
Two Stage ◽  
Ambient Temperatures ◽  
Second Stage ◽  
Energy And Exergy ◽  
Compressor Performance ◽  
Main Engine ◽  
Compressor Efficiency

Data from a two-stage axial vapor cryogenic compressor on the dual-fuel diesel–electric (DFDE) liquefied natural gas (LNG) carrier were measured and analyzed to investigate compressor energy and exergy efficiency in real exploitation conditions. The running parameters of the two-stage compressor were collected while changing the main propeller shafts rpm. As the compressor supply of vaporized gas to the main engines increases, so does the load and rpm in propulsion electric motors, and vice versa. The results show that when the main engine load varied from 46 to 56 rpm at main propulsion shafts increased mass flow rate of vaporized LNG at a two-stage compressor has an influence on compressor performance. Compressor average energy efficiency is around 50%, while the exergy efficiency of the compressor is significantly lower in all measured ranges and on average is around 34%. The change in the ambient temperature from 0 to 50 °C also influences the compressor’s exergy efficiency. Higher exergy efficiency is achieved at lower ambient temperatures. As temperature increases, overall compressor exergy efficiency decreases by about 7% on average over the whole analyzed range. The proposed new concept of energy-saving and increasing the compressor efficiency based on pre-cooling of the compressor second stage is also analyzed. The temperature at the second stage was varied in the range from 0 to −50 °C, which results in power savings up to 26 kW for optimal running regimes.

Steady State Detection in Industrial Gas Turbines for Condition Monitoring and Diagnostics Applications

2014 ◽  
Author(s):  
Cesar Celis ◽  
Érica Xavier ◽  
Tairo Teixeira ◽  
Gustavo R. S. Pinto
Keyword(s):  
Steady State ◽  
Condition Monitoring ◽  
Gas Turbines ◽  
Signal Analysis ◽  
Operating Regime ◽  
State Detection ◽  
Industrial Gas Turbines ◽  
Monitoring And Diagnostics ◽  
Operating Regimes

This work describes the development and implementation of a signal analysis module which allows the reliable detection of operating regimes in industrial gas turbines. Its use is intended for steady state-based condition monitoring and diagnostics systems. This type of systems requires the determination of the operating regime of the equipment, in this particular case, of the industrial gas turbine. After a brief introduction the context in which the signal analysis module is developed is highlighted. Next the state of the art of the different methodologies used for steady state detection in equipment is summarized. A detailed description of the signal analysis module developed, including its different sub systems and the main hypotheses considered during its development, is shown to follow. Finally the main results obtained through the use of the module developed are presented and discussed. The results obtained emphasize the adequacy of this type of procedures for the determination of operating regimes in industrial gas turbines.

Rolls Royce/Allison 501-K Gas Turbine Anti-Fouling Compressor Coatings Evaluation

2002 ◽  
Author(s):  
Daniel E. Caguiat
Keyword(s):  
Gas Turbine ◽  
Fuel Consumption ◽  
Gas Turbines ◽  
Performance Degradation ◽  
Specific Fuel Consumption ◽  
Inlet Temperature ◽  
Test Results ◽  
Turbine Inlet ◽  
Compressor Performance ◽  
Compressor Efficiency

The Naval Surface Warfare Center, Carderock Division (NSWCCD) Gas Turbine Emerging Technologies Code 9334 was tasked by NSWCCD Shipboard Energy Office Code 859 to research and evaluate fouling resistant compressor coatings for Rolls Royce Allison 501-K Series gas turbines. The objective of these tests was to investigate the feasibility of reducing the rate of compressor fouling degradation and associated rate of specific fuel consumption (SFC) increase through the application of anti-fouling coatings. Code 9334 conducted a market investigation and selected coatings that best fit the test objective. The coatings selected were Sermalon for compressor stages 1 and 2 and Sermaflow S4000 for the remaining 12 compressor stages. Both coatings are manufactured by Sermatech International, are intended to substantially decrease blade surface roughness, have inert top layers, and contain an anti-corrosive aluminum-ceramic base coat. Sermalon contains a Polytetrafluoroethylene (PTFE) topcoat, a substance similar to Teflon, for added fouling resistance. Tests were conducted at the Philadelphia Land Based Engineering Site (LBES). Testing was first performed on the existing LBES 501-K17 gas turbine, which had a non-coated compressor. The compressor was then replaced by a coated compressor and the test was repeated. The test plan consisted of injecting a known amount of salt solution into the gas turbine inlet while gathering compressor performance degradation and fuel economy data for 0, 500, 1000, and 1250 KW generator load levels. This method facilitated a direct comparison of compressor degradation trends for the coated and non-coated compressors operating with the same turbine section, thereby reducing the number of variables involved. The collected data for turbine inlet, temperature, compressor efficiency, and fuel consumption were plotted as a percentage of the baseline conditions for each compressor. The results of each plot show a decrease in the rates of compressor degradation and SFC increase for the coated compressor compared to the non-coated compressor. Overall test results show that it is feasible to utilize anti-fouling compressor coatings to reduce the rate of specific fuel consumption increase associated with compressor performance degradation.

scholarly journals Exergy analysis of marine steam turbine labyrinth (gland) seals

Pomorstvo ◽  
2019 ◽  
Vol 33 (1) ◽  
pp. 76-83 ◽  
Author(s):  
Ivan Lorencin ◽  
Nikola Anđelić ◽  
Vedran Mrzljak ◽  
Zlatan Car
Keyword(s):  
Ambient Temperature ◽  
Steam Turbine ◽  
Exergy Analysis ◽  
Numerical Models ◽  
Operating Regime ◽  
Exergy Efficiency ◽  
Specific Enthalpy ◽  
Labyrinth Seals ◽  
Proper Operation ◽  
Operating Regimes

The paper presents an exergy analysis of marine steam turbine labyrinth (gland) seals - an inevitable component of any marine steam turbine cylinder, in three different operating regimes. Throughout labyrinth seals, steam specific enthalpy can be considered as a constant because the results obtained by this assumption do not deviate significantly from the results of complex numerical models. Changes in labyrinth seals exergy efficiency and specific exergy destruction are reverse proportional. The analyzed labyrinth seals have high exergy efficiencies in each observed operating regime at the ambient temperature of 298 K (above 92%), what indicates seals proper operation. An increase in the ambient temperature resulted with a decrease in labyrinth seals exergy efficiency, but even at the highest observed ambient temperature of 318 K, seals exergy efficiency did not fall below 90.5% in each observed operating regime.

Compressor Efficiency Variation With Rotor Tip Gap From Vanishing to Large Clearance

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
S. Sakulkaew ◽  
C. S. Tan ◽  
E. Donahoo ◽  
C. Cornelius ◽  
M. Montgomery
Keyword(s):  
Threshold Value ◽  
Tip Clearance ◽  
Maximum Efficiency ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Flow Mixing ◽  
Viscous Shear ◽  
Clearance Flow ◽  
Compressor Performance ◽  
Compressor Efficiency

Compressor efficiency variation with rotor tip gap is assessed using numerical simulations on an embedded stage representative of that in a large industrial gas turbine with Reynolds number ∼ 2 × 106 to 7 × 106. The results reveal three distinct behaviors of efficiency variation with tip gap. For relatively small tip gap (less than 0.8% span), the change in efficiency with tip gap is nonmonotonic with an optimum tip gap for maximum efficiency. The optimum tip gap is set by two competing flow processes: decreasing tip leakage mixing loss and increasing viscous shear loss at the casing with decreasing tip gap. An optimum tip gap scaling is established and shown to satisfactorily quantify the optimal gap value. For medium tip gap (0.8%–3.4% span), the efficiency decreases approximately on a linear basis with increasing tip clearance. However, for tip gap beyond a threshold value (3.4% span for this rotor), the efficiency becomes less sensitive to tip gap as the blade tip becomes more aft-loaded thus reducing tip flow mixing loss in the rotor passage. The threshold value is set by the competing effects between increasing tip leakage flow and decreasing tip flow induced mixing loss with increasing tip gap. Thus, to desensitize compressor performance variation with blade gap, rotor should be tip aft-loaded and hub fore-loaded while stator should be tip fore-loaded and hub aft-loaded as much as feasible. This reduces the opportunity for clearance flow mixing loss and maximizes the benefits of reversible work from unsteady effects in attenuating the clearance flow through the downstream blade-row. The net effect can be an overall compressor performance enhancement in terms of efficiency, pressure rise capability, robustness to end gap variation, and potentially useful operable range broadening.

Heat Transfer on a Turbocharger Under Constant Load Points

2009 ◽  
Author(s):  
A. Romagnoli ◽  
Ricardo Martinez-Botas
Keyword(s):  
Heat Transfer ◽  
Combustion Engine ◽  
Constant Load ◽  
Heat Transfer Process ◽  
Transfer Model ◽  
Performance Deterioration ◽  
Exit Temperature ◽  
Standard Set ◽  
Compressor Performance ◽  
Compressor Efficiency

The processes occurring in turbo machinery applications are frequently treated as adiabatic. However, in a turbocharger significant heat transfer occurs, leading to a deficit of turbocharger performance. The overall objective of this experimental work is to improve the understanding of the heat transfer process taking place in a turbocharger when installed on an internal combustion engine. In order to do this, beyond the standard set of measurements needed to define the turbo operating point, a large number of thermocouples were installed on the turbocharger. The tests results allow the quantification of the temperatures within the turbocharger and revealed that a nonuniform temperature distribution exists on the compressor and turbine casings. This is partly attributed to the proximity of the turbocharger to the engine. This process plays a role on the deterioration of the compressor efficiency when compared to the corresponding adiabatic efficiency. A correlation that allows the calculation of the compressor exit temperature is proposed. The method uses the surface temperature of the bearing housing; it was validated against experimental data with deviations no larger than 3%. A simplified 1-dimensional heat transfer model was also developed and compared with experimental measurements. The algorithms calculate the heat transferred through the turbocharger, from the hot end to the cold end by means of lump masses. The compressor performance deterioration from the adiabatic map is predicted.

Compressor Efficiency Variation With Rotor Tip Gap From Vanishing to Large Clearance

2012 ◽  
Author(s):  
S. Sakulkaew ◽  
C. S. Tan ◽  
E. Donahoo ◽  
C. Cornelius ◽  
M. Montgomery
Keyword(s):  
Threshold Value ◽  
Tip Clearance ◽  
Maximum Efficiency ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Flow Mixing ◽  
Viscous Shear ◽  
Clearance Flow ◽  
Compressor Performance ◽  
Compressor Efficiency

Compressor efficiency variation with rotor tip gap is assessed using numerical simulations on an embedded stage representative of that in a large industrial gas turbine with Reynolds number ∼ 2 to 7×106. The results reveal three distinct behaviors of efficiency variation with tip gap. For relatively small tip gap (less than 0.8% span), the change in efficiency with tip gap is non-monotonic with an optimum tip gap for maximum efficiency. The optimum tip gap is set by two competing flow processes: decreasing tip leakage mixing loss and increasing viscous shear loss at the casing with decreasing tip gap. An optimum tip gap scaling is established and shown to satisfactorily quantify the optimal gap value. For medium tip gap (0.8%–3.4% span), the efficiency decreases approximately on a linear basis with increasing tip clearance. However, for tip gap beyond a threshold value (3.4% span for this rotor), the efficiency becomes less sensitive to tip gap as the blade tip becomes more aft-loaded thus reducing tip flow mixing loss in the rotor passage. The threshold value is set by the competing effects between increasing tip leakage flow and decreasing tip flow induced mixing loss with increasing tip gap. Thus, to desensitize compressor performance variation with blade gap, rotor should be tip aft-loaded and hub fore-loaded while stator should be tip fore-loaded and hub aft-loaded as much as feasible. This reduces the opportunity for clearance flow mixing loss and maximizes the benefits of reversible work from unsteady effects in attenuating the clearance flow through the downstream blade-row. The net effect can be an overall compressor performance enhancement in terms of efficiency, pressure rise capability, robustness to end gap variation and potentially useful operable range broadening.

scholarly journals Meridional Considerations of the Centrifugal Compressor Development

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
C. Xu ◽  
R. S. Amano
Keyword(s):  
Centrifugal Compressor ◽  
High Efficiency ◽  
Pressure Ratio ◽  
Angle Distribution ◽  
High Pressure Ratio ◽  
Structure Reliability ◽  
Compressor Performance ◽  
Meridional Profile ◽  
Compressor Efficiency ◽  
Wide Operating

Centrifugal compressor developments are interested in using optimization procedures that enable compressor high efficiency and wide operating ranges. Recently, high pressure ratio and efficiency of the centrifugal compressors require impeller design to pay attention to both the blade angle distribution and the meridional profile. The geometry of the blades and the meridional profile are very important contributions of compressor performance and structure reliability. This paper presents some recent studies of meridional impacts of the compressor. Studies indicated that the meridional profiles of the impeller impact the overall compressor efficiency and pressure ratio at the same rotational speed. Proper meridional profiles can improve the compressor efficiency and increase the overall pressure ratio at the same blade back curvature.

The Impact of Bleeding on Compressor Stator Corner Separation

2011 ◽  
Author(s):  
Bin Zhao ◽  
Shaobin Li ◽  
Qiushi Li ◽  
Sheng Zhou
Keyword(s):  
Radial Flow ◽  
Single Stage ◽  
Corner Separation ◽  
Transonic Compressor ◽  
High Pressure Compressor ◽  
Compressor Performance ◽  
The Impact ◽  
Large Flow ◽  
Compressor Efficiency ◽  
Pressure Compressor

Bleed air from the high pressure compressor has taken up 3–5% in the air system. However, there are not many studies on the compressor performance after bleeding. By analyzing a low-speed single-stage compressor and a transonic single-stage compressor, this paper presents several plans with different bleeding rates on the casing near stator corner, in order to study the influence of bleeding rates on the compressor stator corner separation. The results showed that for the stators of subsonic compressor with large flow separation in the corner, there is an optimum value in the stator casing bleed air amount. The flow field is better at resisting the radial flow caused by bleed air in the transonic compressor stator. The more the bleeding rates of the stator, the more the compressor efficiency improves.

Analyses of Centrifugal Compressor Performance Impacts on Volute and Scroll

2010 ◽  
Author(s):  
C. Xu ◽  
R. S. Amano
Keyword(s):  
Static Pressure ◽  
Stokes Equations ◽  
Single Stage ◽  
Navier Stokes ◽  
Performance Tests ◽  
Peak Efficiency ◽  
Navier Stokes Equations ◽  
Flow Simulations ◽  
Compressor Performance ◽  
Compressor Efficiency

Volute is used to collect and transport swirling gas produced by impeller or diffuser. Design of the volute not only impacts compressor efficiency but also influences the operating ranges of the compressor. In this study, Navier-Stokes equations combined with an algebra turbulence model were used to simulate flows inside a single stage compressor. Detailed flow simulations for a large cut back tongue volute are presented and discussed. A rounded tongue volute was tested in a single stage test rig. The compressor stage performance tests were conducted in the test lab and static pressure taps were used to measure static pressures at volute internal walls at locations of θ = 240° and 360°. Thermal couples and other static pressure probes were instrumented at inlet and outlet of the compressor for performance tests. The numerical results were compared with experiments and good agreements are found. Studies showed that a large cut back rounded tongue volute provided good operating range without dramatically dropping compressor peak efficiency.

Sign in / Sign up

Export Citation Format

Share Document