Uncertainty in the Determination of Thermal Efficiency in Natural Gas Engines

2002 ◽  
Author(s):  
John T. Kubesh
Keyword(s):  
Natural Gas ◽  
Thermal Efficiency ◽  
Flow Measurement ◽  
Rate Measurement ◽  
Flow Rate Measurement ◽  
Fuel Flow Rate ◽  
Natural Gas Engines ◽  
Sources Of Uncertainty ◽  
Fuel Flow

This paper discusses the measurement of thermal efficiency for natural gas-fueled engines and the resulting uncertainty. Two methods for determining thermal efficiency are described in detail. For each method, the sources of uncertainty are identified and quantified, and an estimate of the overall uncertainty is calculated. The analysis indicates that a thermal efficiency calculation that uses a mass fuel flow rate measurement directly as a basis for the energy input rate provides less uncertainty than the other method that uses a volumetric flow measurement.

Accurate and Continuous Fuel Flow Rate Measurement Prediction for Real Time Application

2011 ◽  
Vol 4 (1) ◽  
pp. 1724-1737 ◽  
Author(s):  
Jiamei Deng ◽  
Bastian Maass ◽  
Richard Stobart ◽  
Edward Winward ◽  
Zhijia Yang
Keyword(s):  
Real Time ◽  
Flow Rate ◽  
Rate Measurement ◽  
Flow Rate Measurement ◽  
Fuel Flow Rate ◽  
Fuel Flow ◽  
Real Time Application

Invariant method for measuring wet gas flow rate

2021 ◽  
pp. 13-19
Author(s):  
Zhanat А. Dayev ◽  
Gulzhan E. Shopanova ◽  
Bakytgul А. Toksanbaeva
Keyword(s):  
Flow Rate ◽  
Measurement System ◽  
Flow Measurement ◽  
Gas Flow ◽  
Test Results ◽  
Invariant System ◽  
Rate Measurement ◽  
Gas Flow Rate ◽  
Flow Rate Measurement ◽  
Wet Gas

The article deals with one of the important tasks of modern flow measurement, which is related to the measurement of the flow rate and the amount of wet gas. This task becomes especially important when it becomes necessary to obtain information about the separate amount of the dry part of the gas that is contained in the form of a mixture in the wet gas stream. The paper presents the principle of operation and structure of the invariant system for measuring the flow rate of wet gas, which is based on the combined use of differential pressure flowmeters and Coriolis flowmeters. The operation of the invariant wet gas flow rate measurement system is based on the simultaneous application of the multichannel principle and the partial flow measurement method. Coriolis flowmeters and the differential pressure flowmeter are used as the main elements of the system. The proposed measurement system does not offer applications for gases with abundant drip humidity. The article provides information about the test results of the proposed invariant system. The estimation of the metrological characteristics of the invariant system when measuring the flow rate of wet gas is given. The obtained test results of the invariant wet gas flow rate measurement system are relevant for natural gas production, transportation, and storage facilities.

scholarly journals A Method to Measure the Fuel Distribution and the Fuel Captured by V–Gutter Flameholder in High Speed Airstream

1985 ◽  
Author(s):  
Gu Shan-Jian ◽  
Yang Mao-Lin ◽  
Li Xiang-Yi
Keyword(s):  
Flow Rate ◽  
Experimental Error ◽  
High Speed ◽  
Fuel Flow Rate ◽  
Fuel Distribution ◽  
Fuel Flow ◽  
Sampling Condition ◽  
Detailed Determination

A method to measure the fuel distribution and the percentage of fuel flow rate captured by a V-gutter flameholder in a high speed airstream has been developed. The effects of configuration and size of the probe and temprature of the sample mixture in the probe on measurement have been investigated. The detailed determination of isokinetic sampling condition is described. The effects of V-gutter geometry on flowfield have been considered. The total experimental error is of the order ±5%.

Comparative Analysis of EGR and Air Dilution in Spark-Ignited Natural Gas Engines

2017 ◽  
Author(s):  
William Glewen ◽  
Chris Hoops ◽  
Joel Hiltner ◽  
Michael Flory
Keyword(s):  
Natural Gas ◽  
Power Density ◽  
Thermal Efficiency ◽  
Gas Temperature ◽  
Natural Gas Engines ◽  
Cycle Simulation ◽  
Wide Range ◽  
Charge Mixture ◽  
The Impact ◽  
Three Way Catalyst

Industrial natural gas engines are used in a wide range of applications, each with unique requirements in terms of power density, initial cost, thermal efficiency, and other factors. As a result of these requirements, distinct engine designs have evolved to serve various applications. Heavy-duty spark-ignited engines can generally be divided into two broad categories based on their charge characteristics and method of emissions control. Stoichiometric engines are widely used in applications where first cost, absolute emissions and relative engine simplicity are more important than fuel consumption. In most of the developed world, stoichiometric engines are equipped with a three-way catalyst to control emissions of nitrogen oxides (NOx) as well as products of incomplete combustion and raw unburned fuel. Dilution of the charge mixture with excess air reduces the peak combustion gas temperature and associated heat rejection. As a result, lean burn engines are generally able to achieve higher efficiency and power density without inducing excessive component temperatures or end gas knock. NOx formation is mitigated by the reduced gas temperatures, such that most regulatory standards can currently be met in-cylinder. Significant obstacles exist to meeting more stringent future emissions regulations in this manner, however. Another possible strategy is to dilute the charge mixture with recirculated exhaust gas. This offers similar benefits as air dilution while maintaining the ability to use a three-way catalyst for emissions after-treatment. While similar principles apply in either case, the choice of diluent can have a significant impact on knock resistance, emissions formation, thermal efficiency, and other parameters of importance to engine developers and operators. This work aimed to examine the unique characteristics of EGR and air dilution from a thermodynamic and combustion perspective. A combination of cycle simulation tools and experimental data from a single-cylinder test engine was applied to demonstrate the impact of diluent properties on a fundamental level, and to illustrate departures from idealized behavior and practical considerations specific to the development of combustion systems for spark-ignited natural gas engines.

Computational Fluid Dynamic Analyses of Flow and Combustion in a Domestic Liquefied Petroleum Gas Cookstove Burner—Part II: Burning Characteristics and Overall Performance

2019 ◽  
Vol 12 (3) ◽  
Author(s):  
Mithun Das ◽  
Ranjan Ganguly ◽  
Amitava Datta ◽  
Meenam M. Verma ◽  
Ashis K. Bera
Keyword(s):  
Heat Flux ◽  
Flow Rate ◽  
Thermal Efficiency ◽  
Equivalence Ratio ◽  
Vessel Diameter ◽  
High Energy ◽  
Liquefied Petroleum Gas ◽  
Fuel Flow Rate ◽  
Fuel Flow ◽  
Load Height

Abstract Liquefied petroleum gas (LPG) is widely used in domestic cookstoves as it is a clean and high energy content fuel in comparison with other traditional cooking fuels. With the increasing demand of LPG, study and improvement of cookstove performance have become an important subject. In the present work, a numerical study of the flow and thermal fields for a domestic cookstove burner has been investigated and the performance of the stove is analyzed at different parametric conditions, like the equivalence ratio of the primary fuel–air mixture, fuel flow rate, thermal load height, and loading vessel size. The maximum thermal efficiency has been found for an equivalence ratio of 1.4 for the LPG–air mixture and at load height of 20 mm. The heat flux distribution at the bottom of the vessel is found to be bimodal with the higher peak occurring closer to the center of the vessel. The thermal efficiency of the stove increases with the rise in the fuel flow rate, and it decreases with reducing cooking vessel diameter. As the vessel diameter increases, the fraction of the total heat supplied through the vessel bottom increases. The radiative component of the heat flux is found to be much smaller compared to the convective component.

Effects of Spark Plug Number and Location in Natural Gas Engines

1992 ◽  
Vol 114 (3) ◽  
pp. 475-479 ◽  
Author(s):  
R. C. Meyer ◽  
D. P. Meyers ◽  
S. R. King ◽  
W. E. Liss
Keyword(s):  
Natural Gas ◽  
Thermal Efficiency ◽  
Cylinder Pressure ◽  
Natural Gas Engines ◽  
Single Cylinder Engine ◽  
Spark Plug ◽  
Combustion Duration ◽  
Peak Cylinder Pressure ◽  
Wide Range ◽  
Pressure Peak

Combustion experiments were conducted on a spark-ignited single-cylinder engine operating on natural gas. A special open chamber cylinder head was designed to accept as many as four spark plugs. Data were obtained to investigate the effects of spark plug quantity and location on NOx, HC, CO emissions, brake and indicated thermal efficiency, MBT timing, combustion duration, ignition delay, peak cylinder pressure, peak cylinder temperature, and heat release over a wide range of equivalence ratios.

Design and Development of a Direct Injected, Glow Plug Ignition-Assisted, Natural Gas Engine

1995 ◽  
Vol 117 (4) ◽  
pp. 799-803 ◽  
Author(s):  
M. L. Willi ◽  
B. G. Richards
Keyword(s):  
Natural Gas ◽  
Thermal Efficiency ◽  
Natural Gas Engines ◽  
Natural Gas Engine ◽  
Fuel Ratio ◽  
Component Design ◽  
Engine Component ◽  
Diesel Cycle ◽  
Laboratory Development ◽  
Performance Development

Conventional (Otto cycle) natural gas engines are limited in power and thermal efficiency relative to a diesel engine due to detonation and the need to run a nearly stoichiometric air/fuel ratio. Technology is under development to burn natural gas in a direct-injected diesel cycle that is not prone to detonation or air/fuel ratio control limitations. Direct-injected gas (DIG) technology will allow natural gas engines to match the power and thermal efficiency of the equivalent diesel-fueled engine. Laboratory development now under way is targeted for field experimental evaluation of a DIG 3516 engine in a 1500 kW road switcher locomotive. This paper will describe DIG 3516 engine component design and single and multicylinder performance development.

Modified Brayton Cycle for Turbofans

2019 ◽  
Author(s):  
Chirag Singhal ◽  
Sameer Hasan ◽  
M. F. Baig
Keyword(s):  
Flow Rate ◽  
Thermal Efficiency ◽  
Pressure Ratio ◽  
Enthalpy Of Combustion ◽  
Inlet Temperature ◽  
Brayton Cycle ◽  
Percentage Increase ◽  
Fuel Flow Rate ◽  
Fuel Flow ◽  
Total Thrust

Abstract In the present study, a design point analysis of twin-spool turbofan engines is carried out, considering fuel injection of Aviation Turbine Fuel (ATF) in the initial stages of the compressor instead of combustor The two-phase compression brings about intercooling in the modified Brayton cycle, by injecting the atomized fuel directly in the initial stages of axial-flow compressor. The intercooling effect results in reduction of compressor work while reinforcing the enthalpy of combustion of fuel due to change of state of fuel from liquid to vapor state. This brings about an improvement in the thrust and thermal efficiency of the modified cycle. Effect of the intercooling is investigated for different performance parameters namely Fuel flow rate ṁf Total thrust Fs, Thermal efficiency ηth, Overall efficiency ηo and Modified cycle factor MCF over the varying compressor pressure ratio (CPR). Injecting the fuel in the 2nd stage of compression results in percentage increase of total thrust by 21.14%, MCF by 31.35%, ηo by 14.92% and decrease in Fuel flow rate ṁf by 7%. While injecting the fuel in the 5th stage of compression results in increased ηo by 17.54 %, MCF by 37.30%, total thrust by 5.68% and decrease in Fuel flow rate ṁf by 22% at a CPR = 30 and Turbine Inlet Temperature (TIT) = 1260K vis-à-vis conventional cycle. Injecting the fuel in latter stages of compressor brings about a decrease of total thrust as well as efficiency.

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