References of "Ngendakumana, Philippe"
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See detailPrediction of SOx and NOx Emissions from a Medium Size Biomass Boiler Biomass and Bioenergy
Sartor, Kevin ULg; Restivo, Yannick ULg; Ngendakumana, Philippe ULg et al

in Biomass and Bioenergy (2014), 65

While small and medium size biomass combined heat and power (CHP) plants (i.e., up to 5 MW of electrical rated power) represent an attractive option to exploit locally available biomass resources at low ... [more ▼]

While small and medium size biomass combined heat and power (CHP) plants (i.e., up to 5 MW of electrical rated power) represent an attractive option to exploit locally available biomass resources at low cost, the corresponding investment per unit of rated power significantly rises when the installed power decreases. In these cases, secondary pollutant emissions control measures are most of the time not economically viable and primary emissions control must be used alone to avoid the formation of undesired compounds such as $NO_x$ and $SO_x$. Primary control measures require the careful optimization of fuel quality and combustion process. For plant operators, being able to accommodate biomass quality changes in order to minimize the fuel cost can be of great importance in order to guarantee the profitability of the plant. This contribution is dedicated to the development of a zero-dimensional (input-output) combustion simulation model able to predict the pollutants emissions resulting from complete and incomplete combustion with respect to varying combustion operation (ambient temperature, humidity, fumes recirculation,..). This tool is intended to be integrated in a global simulation model of the CHP plant and the attached district heating network installed on the University campus in Liège. Doing so, the plant operation can be optimized with respect to economic as well as environmental and energetic aspects (3E approach) thus ensuring the sustainability of the approach. [less ▲]

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See detailOptimization of the operating conditions of an existing biomass CHP plant with respect to pollutants levels
Sartor, Kevin ULg; Restivo, Yannick ULg; Ngendakumana, Philippe ULg et al

in Proceedings of 21st Biomass Conference and Exhibition (2013, June 03)

While small and medium size biomass combined heat and power plants (i.e., up to 5 MW of electrical rated power) represent an attractive option to exploit locally available biomass resources at low cost ... [more ▼]

While small and medium size biomass combined heat and power plants (i.e., up to 5 MW of electrical rated power) represent an attractive option to exploit locally available biomass resources at low cost, the corresponding investment per unit of rated power significantly rises when the installed power decreases. In these cases, secondary pollutant emissions control measures are most of the time not economically viable and primary emissions control must be used alone to avoid the formation of undesired compounds such as $NO_x$ and $SO_x$. Primary control measures require the careful optimization of fuel quality and combustion process. For plant operators, being able to accommodate biomass quality changes in order to minimize the fuel cost can be of great importance in order to guarantee the profitability of the plant. This contribution is dedicated to the development of zero-dimensional (input-output) combustion simulation model able to predict the pollutants emissions resulting from complete and incomplete combustion with respect to varying combustion operation (ambient temperature, humidity, fumes recirculation,..). This tool is intended to be integrated in global simulation model of the CHP plant and the attached district heating network installed on the University campus in Liège. Doing so, the plant operation can be optimized with respect to economic as well as environmental and energetic aspects (3E approach) thus ensuring the sustainability of the approach. [less ▲]

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See detailThermo-hydraulic characterization of an automotive intercooler for a low pressure EGR application
Cuevas, Cristian; Makaire, Danielle ULg; Ngendakumana, Philippe ULg

in Applied Thermal Engineering (2011), 31(14-15), 2474-2484

In this work an experimental study is carried out to determine the thermo-hydraulic performance of an intercooler (IC) with flat tubes provided with triangular plain internal fins and louvered external ... [more ▼]

In this work an experimental study is carried out to determine the thermo-hydraulic performance of an intercooler (IC) with flat tubes provided with triangular plain internal fins and louvered external fins when it is used on a car equipped with a low pressure EGR. The main unknowns to be answered are the thermo-hydraulic characteristics of the IC working under humid conditions induced by EGR, the conditions under which the water content in the mixture of air and exhaust gases begins to condense and the conditions under which the condensed water will be retained inside the IC. The exhaust gases are here replaced by a mixture of dry air and water vapour which are mixed upstream of the IC. The IC is submitted at the following testing conditions: on the ambient air side, the air temperature is fixed at around 20 °C and the air velocity is settled at 1, 2 and 4 ms/s; on the exhaust gases side, the supply temperature was varied between 90 and 150 °C, with dry gas flow rates of 20, 50 and 100 g /s, and water contents varying between almost 0 and 0.09 kgw kgg-1. At these conditions the IC transfers between 1 and 13 kW with overall heat transfer conductance varying between 0.05 and 0.38 kWK-1 and effectivenesses between 0.3 and 0.97. A water accumulation inside the IC was detected for the tests carried out at low dry gas flow rate of 20 g s-1 and for all the water content explored here (higher than 0.02 kgw kgg-1). [less ▲]

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See detailThe use of liquid biofuels in heating systems: a review
Makaire, Danielle ULg; Sartor, Kevin ULg; Ngendakumana, Philippe ULg

Conference (2011, August)

European Union has set the 2020 strategy to increase the share of renewable energy use to 20% by 2020. Currently, most attention is focussed on the use of alternative fuels from biomass for energy ... [more ▼]

European Union has set the 2020 strategy to increase the share of renewable energy use to 20% by 2020. Currently, most attention is focussed on the use of alternative fuels from biomass for energy purposes. These alternative fuels are called bioliquids. This paper reviews the current experimental works that have been performed on the combustion of vegetable oil, biodiesel and bioethanol in various heating combustion units. This review focuses on the feasibility of bioliquids use in heating systems as well as their “environmental friendly” potential. [less ▲]

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See detailCombustion control and performance of household condensing boilers
Makaire, Danielle ULg; Ngendakumana, Philippe ULg

Poster (2011, April)

The present work presents a model that is composed of a conventional boiler model with a main counterflow gas-water heat exchanger at which a condensing heat exchanger is added. Prior to the second heat ... [more ▼]

The present work presents a model that is composed of a conventional boiler model with a main counterflow gas-water heat exchanger at which a condensing heat exchanger is added. Prior to the second heat exchanger the exhaust gas are converted to equivalent wet air as the wet heat exchanger is simulated by a cooling coil used in air treatment. Six parameters are needed for calculation and these parameters are fitted with experimental data: one test in dry regime and one test in wet regime. Steady-state tests have been performed on two household boilers (a gas-fired and a fuel oil boiler), whose nominal outputs are 24 kW in order to fit the model parameters and check the model behaviour. It seems that the model gives the correct trend for the thermal efficiency prediction. Besides, combustion controls sensors (non nernstian sensors) have been tested by varying the excess of air. In the range tested (from =1.05 to =1.25), the increase in the boiler efficiency is around 1% as the excess of air decreases. However that increase is lower than the measurement uncertainty. The developed model predicts very well that trend. The pollutants emissions have also been measured and the results show that the NOx emissions decrease as the excess air increases. [less ▲]

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See detailStudy of the feasibility of burning neat jatropha oil into a vaporizing burner for household applications
Makaire, Danielle; Fontaine, Jean-Marie; Sartor, Kevin ULg et al

in Biomass & Bioenergy (2011)

Charcoal is one of the major energy sources for household applications in urban areas of developing countries. It is often made from natural forest and accelerates forest depletion. The aim of this work ... [more ▼]

Charcoal is one of the major energy sources for household applications in urban areas of developing countries. It is often made from natural forest and accelerates forest depletion. The aim of this work was to evaluate the use of jatropha oil for combustion in vaporizing burners. This paper presents laboratory tests on a burner whose nominal output is 7.5kW. The burner had to be modified because of the high viscosity of jatropha oil and for cold start, as the oil flash point is much higher than fuel oil flash point. Pollutants emissions and thermal performances are analyzed for three firing rates. The burner meets EN1 standards at high firing rate. Unburned emissions are higher for middle and low firing rates. [less ▲]

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See detailThermo-hydraulic Characterization of a Louvered Fin and Flat Tube Heat Exchanger
CUEVAS, Cristian; Makaire, Danielle ULg; DARDENNE, Laurent et al

in Experimental Thermal & Fluid Science (2011), (1), 154164

In the present study, a whole heat exchanger with a hydraulic diameter of 2.3 mm is tested, which is a minichannel heat exchanger according to the Kandlikar classification. This is a louvered fin and flat ... [more ▼]

In the present study, a whole heat exchanger with a hydraulic diameter of 2.3 mm is tested, which is a minichannel heat exchanger according to the Kandlikar classification. This is a louvered fin and flat tube heat exchanger currently used in car cooling systems, also known as radiator. A glycol-water mixture (60/40 in volume) circulates through the tubes at flows ranging from 100 to 7800 l/h and at a supply temperature of 90ºC. This fluid is cooled with ambient air at a temperature of 20ºC and at frontal air velocities varying between 0.5 and 7 m/s. The thermohydraulic performance of the heat exchanger is compared with the classical correlations given in the literature for the heat transfer and the friction factor calculation. On the glycolwater side the heat exchanger is characterized for Reynolds numbers from 30 to 8000. A first comparison is carried out with the correlations available in the literature with a purely predictive model by obtaining a predictive value with a systematic under prediction lower than 10%. In a second step a semi-empirical model is considered to identify the experimental heat transfer coefficients for this application. [less ▲]

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See detailOn the spectral bands measurements for combustion monitoring
Arias, Luis; Torres, S; Sbarbaro, D et al

in Combustion and Flame (2011), 158

In this work, spatial–spectral experimental issues affecting the detection of radical emissions in a natural gas flame are discussed and studied by a radiometric analysis of the flame spectral emission ... [more ▼]

In this work, spatial–spectral experimental issues affecting the detection of radical emissions in a natural gas flame are discussed and studied by a radiometric analysis of the flame spectral emission. As results of this analysis, Local and Global Spectral Radiation Measurements (LSRM and GSRM respectively) techniques are proposed, and guidelines for selecting the radical emission bands and spatial location of photodetectors are given. Two types of experiments have been performed in order to demonstrate the reliability of the GSRM technique for combustion characterization. In the first experiment, the LSRM and the GSRM have been implemented by using a home made sensor array, based on silicon photodiodes, for sensing the excited CH* and C2 radicals in a natural gas flame. It has been experimentally that by using the GSRM, the signal’s dispersion can be reduced to about 86% for the CH* and 76% for the C2 with respect to the obtained values with LSRM methodology. In the second experiment, the GSRM technique has been applied for sensing the CH* and C2 radicals, where it has been found that the signals emissions ratio C2/CH* provides a good indicator of the thermal combustion efficiency and the CO pollutants emissions, with small dispersion. Thus, the GSRM technique has corroborated the usefulness of that ratio for combustion monitoring. [less ▲]

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See detailThermal performance of condensing boilers
Makaire, Danielle ULg; Ngendakumana, Philippe ULg

Scientific conference (2010, July)

Nowadays, condensing technology is widely used in space heating. This paper presents a model that predicts thermal performance of condensing boilers. The structure of the model is similar to the one of a ... [more ▼]

Nowadays, condensing technology is widely used in space heating. This paper presents a model that predicts thermal performance of condensing boilers. The structure of the model is similar to the one of a conventional boiler model with a dry heat exchanger at which a wet heat exchanger is added to simulate the heat recovered by condensation. Tests have been performed on two household 24 kW condensing boilers (gas- and oil-fired boilers). The experimental results are compared to the simulated values. According to the results, the model correctly predicts the thermal efficiency of the boiler. Indeed, predicted values are in good agreement with measured values (if one takes into account the measurements uncertainties). [less ▲]

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See detailSIMULATION MODEL OF A GAS-FIRED CONDENSING BOILER AT FULL LOAD OPERATION IN STEADY-STATE REGIME
Makaire, Danielle ULg; Ngendakumana, Philippe ULg

in ASME-ATI-UIT 2010 Conference on Thermal and Environmental Issues in Energy Systems (2010, May)

The model in this paper was developed to predict thermal performances of gas-fired condensing boilers. The structure of the developed model is similar to the one of a conventional boiler with a main ... [more ▼]

The model in this paper was developed to predict thermal performances of gas-fired condensing boilers. The structure of the developed model is similar to the one of a conventional boiler with a main counterflow gas-water heat exchanger, at which a condensing heat exchanger is added. Prior to the second heat exchanger, the exhaust gas are converted into equivalent wet air. The condensing heat exchanger is divided into smaller parts and each part is simulated by a cooling coil model currently used in HVAC simulation. Several tests have been performed in steady-state regime on a household gas-fired boiler whose nominal output is 24 kW. The experimental results are compared to the model results and the results are discussed. [less ▲]

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See detailModèle de simulation des performances d'une chaudière fioul à condensation de chauffage domestique
Makaire, Danielle ULg; Ngendakumana, Philippe ULg

in Energies et transports durables : SFT10, Le Touquet 25-28 mai 2010 (2010, May)

The developed model in this work is similar to a classical model of a conventional boiler (combination of a combustion chamber and a water-flue gas heat exchanger) to which a model of a heat exchanger for ... [more ▼]

The developed model in this work is similar to a classical model of a conventional boiler (combination of a combustion chamber and a water-flue gas heat exchanger) to which a model of a heat exchanger for condensation has been added. This latter has been simulated by a cooling coil divided into several elements The developed model has been applied on a condensing whose nominal useful power is 24.6 KW. After the determination of the nominal parameters, tests have been performed to validate the model in different working conditions of the boiler. The two main parameters whose influence has been investigated are : the return water temperature and the overall excess air. [less ▲]

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See detailModelling the thermal efficiency of condensing boilers working in steady-state conditions
Makaire, Danielle ULg; Ngendakumana, Philippe ULg

Scientific conference (2010, May)

The structure of the model is similar to the model of a conventional boiler model with a main counterflow gas-water heat exchanger (HX1), at which a condensing heat exchanger is added (HX2). The case ... [more ▼]

The structure of the model is similar to the model of a conventional boiler model with a main counterflow gas-water heat exchanger (HX1), at which a condensing heat exchanger is added (HX2). The case losses to the ambient is neglected. Prior to the second heat exchanger (HX2), the exhaust gas are converted to equivalent wet air as the wet heat exchanger is simulated by a cooling coil used in air treatment. The model has been validated experimentally on gas- and oil-fired boilers. Calculated thermal efficiencies agree very well with experimental results. [less ▲]

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See detailNatural Gas as an Alternative Fuel for Spark Ignition Engines
Sartor, Kevin ULg; Ngendakumana, Philippe ULg

Scientific conference (2010, May)

Detailed reference viewed: 47 (11 ULg)
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See detailAir–Hydrogen Heat Exchangers for Advanced Space Launchers
Hendrick, Patrick; Heintz, Nicolas; Bizzarri, Didier et al

in Journal of Propulsion and Power (2009), 25(6),

This paper deals with air–hydrogen heat exchangers intended to provide in-flight oxygen collection capability to a reusable or semireusable two-stages-to-orbit launcher with an oxygen collection phase in ... [more ▼]

This paper deals with air–hydrogen heat exchangers intended to provide in-flight oxygen collection capability to a reusable or semireusable two-stages-to-orbit launcher with an oxygen collection phase in supersonic cruise at Mach 2.5. It aims to present a theoretical but mainly technological and experimental feasibility study of heat exchangers sufficiently efficient and reliable to suit the extreme requirements of this application. Two precoolers of two different types (shell and tubes, and plate and fins) have been selected and designed with the objective of fulfilling all constraints of the concept in terms of performance, leak tightness, reliability, compactness, etc. This design process has been validated with four subscaled breadboards (two of each type) tested on two test benches (for performance and leak tightness), developed by Belgium and Spain, in on-design and off-design conditions. All these results highlight the suitability of the new technologies given the extreme requirements of the concept. An optimum design for each technology is recommended considering its proper advantages and disadvantages. An innovative precooler technology is presented and tested. [less ▲]

Detailed reference viewed: 51 (4 ULg)