Effects of Air Temperature on Combustion Characteristics of LPG Diffusion Flame

2020 ◽  
Vol 1008 ◽  
pp. 128-138
Author(s):  
Ahmed M. Salman ◽  
Ibrahim A. Ibrahim ◽  
Hamada M. Gad ◽  
Tharwat M. Farag
Keyword(s):  
Air Temperature ◽  
Diffusion Flame ◽  
Nitrogen Addition ◽  
Flame Length ◽  
Combustion Characteristics ◽  
Operating Conditions ◽  
Low Oxygen ◽  
Air Temperatures ◽  
Air Stream ◽  
Wide Range

In the present study, the combustion characteristics of LPG gaseous fuel diffusion flame at elevated air temperatures were experimentally investigated. An experimental test rig was manufactured to examine a wide range of operating conditions. The investigated parameters are the air temperatures of 300, 350, 400, 450, and 500 K with constant percentage of nitrogen addition in combustion air stream of 5 % to give low oxygen concentration of 18.3 % by mass at constant air swirl number, air to fuel mass ratio, and thermal load of 1.5, 30, and 23 kW, respectively. The gaseous combustion characteristics were represented as axial and radial temperatures distributions, temperatures gradient, visible flame length and species concentrations. The results indicated that as the air temperature increased, the chemical reaction rate increased and flame volume decreased, the combustion time reduced leading to a reduction in flame length. The NO concentration reaches its maximum values near the location of the maximum centerline axial temperature. Increasing the combustion air temperature by 200 K, the NO consequently O2 concentrations are increased by about % 355 and 20 % respectively, while CO2 and CO concentrations are decreased by about % 21 and 99 % respectively, at the combustor end.

Modified Chilled Coil Model Development and Application to Turbine Inlet Air Cooling

2021 ◽  
Vol 29 (01) ◽  
pp. 2150006
Author(s):  
Gopalakrishnan Anand ◽  
Ellen Makar
Keyword(s):  
Air Temperature ◽  
Flow Rate ◽  
Operating Conditions ◽  
Performance Data ◽  
Surface Model ◽  
Air Cooling ◽  
Ambient Temperatures ◽  
Turbine Inlet ◽  
Wide Range ◽  
Coil Performance

A Turbine Inlet Air Conditioning (TIAC) system can chill the inlet air of the turbine to maintain maximum turbine performance at all ambient temperatures. However, turbine characteristics, performance guarantees and bell-mouth icing considerations require accurate prediction of the chilling coil performance over a wide range of operating conditions. A modified wet-surface model (MWSM) is developed to more accurately predict the chilling coil performance. The higher accuracy of the model is demonstrated by applying the model to simulate performance data of two different coils. The data covered a wide range of operating conditions with ambient temperature vary from [Formula: see text]C to [Formula: see text]C dry bulb and [Formula: see text]C to [Formula: see text]C wet bulb. The turbine flow rate varies from 100% to 43% with chilled air temperature in the range of 3.3–[Formula: see text]C and chilling load variation of 100% to 5%. The chilled water flow rate varies from 100% to 32% with supply glycol-water temperature in the range of [Formula: see text]2.2–[Formula: see text]C. The MWSM uses 11 empirical parameters evaluated from the coil performance data and is able to correlate the data with an adjusted coefficient of determination ([Formula: see text]) of over 99%. The higher accuracy of the modified model enables the development of a more robust controls strategy required to maintain the inlet air temperature at the set point with varying ambient temperatures and chilling load conditions. The model can also be applied to other chilling and dehumidification applications especially those experiencing wide variations in operating conditions and load or those requiring close control of the chilling and dehumidification process.

An Experimental Investigation of HCCI Combustion Stability Using N-Heptane

2007 ◽  
Author(s):  
Hailin Li ◽  
W. Stuart Neill ◽  
Wally Chippior ◽  
Joshua D. Taylor
Keyword(s):  
Heat Release ◽  
Flow Rate ◽  
Combustion Process ◽  
Operating Conditions ◽  
Combustion Stability ◽  
Fuel Flow Rate ◽  
Fuel Flow ◽  
Air Temperatures ◽  
Wide Range ◽  
Cyclic Variations

In this paper, cyclic variations in the combustion process of a single-cylinder HCCI engine operated with n-heptane were measured over a range of intake air temperatures and pressures, compression ratios, air/fuel ratios, and exhaust gas recirculation (EGR) rates. The operating conditions produced a wide range of combustion timings from overly advanced combustion where knocking occurred to retarded combustion where incomplete combustion was detected. Cycle-to-cycle variations were shown to depend strongly on the crank angle phasing of 50% heat release and fuel flow rate. Combustion instability increased significantly with retarded combustion phasing especially when the fuel flow rate was low. Retarded combustion phasing can be tolerated when the fuel flow rate is high. It was also concluded that the cyclic variations in imep are primarily due to the variations in the total heat released from cycle-to-cycle. The completeness of the combustion process in one cycle affects the in-cylinder conditions and resultant heat release in the next engine cycle.

Parental Care and the Development of Thermoregulation in Red Junglefowl

Behaviour ◽  
1981 ◽  
Vol 76 (3-4) ◽  
pp. 250-279 ◽  
Author(s):  
D.F. Sherry
Keyword(s):  
Body Temperature ◽  
Air Temperature ◽  
Behavioural Thermoregulation ◽  
Thermal Environments ◽  
Air Temperatures ◽  
Red Junglefowl ◽  
Wide Range ◽  
In The Wild ◽  
Elevated Body Temperature ◽  
Brooding Behaviour

AbstractFew newly hatched birds are capable of maintaining a stable elevated body temperature at air temperatures encountered in the wild. The brooding behaviour of young red junglefowl (Gallus gallus spadiceus) and the changes in brooding that occur with the development of homeothermy were examined to determine the importance of thermal factors in parent-young contact. A fall in cooling rate and a rise in body temperature occur in junglefowl chicks in the days following hatching, and the young spend less time in contact with the hen as these changes occur. The length of brooding bouts is jointly determined by air temperature and the age of the young. Additional brooding at low air temperatures did not affect feeding by the parent or young. The general features of chick brooding persist when the hen is replaced with a model with brood patches at a temperature normal for maternal junglefowl. Brooding and huddling with other young are alternative thermoregulatory strategies. Behavioural thermoregulation by the young accounted for most features of contact between parent and young. Termination of brooding by the parent and reduction of chick heat loss by changes in parental posture may also influence brooding. Reliance on behavioural thermoregulation may permit development in a wide range of thermal environments.

scholarly journals Initiative use of climate change hotspots for targeting adaptation sites in Indonesia

2021 ◽  
Vol 893 (1) ◽  
pp. 012035
Author(s):  
Ikrom Mustofa ◽  
Perdinan ◽  
Syafararisa Dian Pratiwi ◽  
Suvany Aprilia ◽  
Raden Eliasar Prabowo Tjahjono ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Change Adaptation ◽  
Air Temperature ◽  
Climate Model ◽  
Climate Change Impacts ◽  
Base Temperature ◽  
Economic Sectors ◽  
Air Temperatures ◽  
Wide Range ◽  
Increasing Temperature

Abstract Designing climate change adaptation actions are considerably a challenge, as the actions should be targeted uniquely addressing climate change impacts. One of the challenges is to determine climate change adaptation sites. The complexity raises considering climate change impact a wide range of economic sectors, which require a lot of resources to conduct a comprehensive climate change assessments. This study proposes the use of climate change hotspots as an initiative to firstly consider the potential targeted sites. The target of global efforts to maintain air temperature under 2°C was employed as a clue to prioritize areas that air temperature is increasing beyond the thresholds to which can affect human activities. This study employed spatial and threshold analysis to develop climate change hotspots of projected temperature change for 2021-2050 over Indonesia. The thresholds were defined by considering the effects of base temperature of 32 °C, 35 °C, and 38 °C on agriculture, environment, and human health in combination with elevated temperature from 0.75 to 2 °C. The initiative method was applied to the baseline and projected air temperature obtained from higher resolution of climate model outputs simulated under representative carbon pathway scenario of 4.5 (RCP 4.5 and 8.5) as a case study. The maps of climate change hotspots provide the potential targeted areas for climate change adaptation actions. Referring to the target of suppressing global temperatures below 2°C, we identified the distribution of climate change hotspots in Indonesia with a scenario of increasing temperature of 2°C from baseline conditions so that future air temperatures will be more than 35°C. The maps can also be combined with the other maps related to climate change analyses, which are available in Indonesia such as SIDIK to refine the priority areas and/or more general geographic information such as city location. As an example, the overlay of climate change hotspots and city location can provide early anticipation on which city will experience urban heat island. The development of climate change hotspots nationally is also expected to initiate climate change services that can be provided to the end users to ease them in defining suitable actions to adapt to the impacts of climate change.

scholarly journals Infrared Interferometric Measurements of the Near-Surface Air Temperature over the Oceans

2005 ◽  
Vol 22 (7) ◽  
pp. 1019-1032 ◽  
Author(s):  
P. J. Minnett ◽  
K. A. Maillet ◽  
J. A. Hanafin ◽  
B. J. Osborne
Keyword(s):  
Air Temperature ◽  
Surface Air Temperature ◽  
The Arctic ◽  
Heat Island ◽  
Radiometric Measurement ◽  
Near Surface ◽  
Air Temperatures ◽  
Wide Range ◽  
Marine Air ◽  
The Tropical Pacific

Abstract The radiometric measurement of the marine air temperature using a Fourier transform infrared spectroradiometer is described. The measurements are taken by the Marine-Atmospheric Emitted Radiance Interferometer (M-AERI) that has been deployed on many research ships in a wide range of conditions. This approach is inherently more accurate than conventional techniques and can be used to determine some of the error characteristics of the standard measurements. Examples are given from several cruises ranging from the Arctic to the equatorial Pacific Oceans. It is shown that the diurnal heating signal in radiometric air temperatures in the tropical Pacific can typically reach an amplitude of ∼15% of that measured by conventional sensors. Conventional data have long been recognized as being contaminated by direct solar heating and heat island effects of the ships or buoys on which they are mounted, but here this effect is quantified by comparisons with radiometric measurements.

scholarly journals Performance of low-pressure fans operating with hot air

2016 ◽  
Vol 20 (suppl. 5) ◽  
pp. 1435-1447
Author(s):  
Jasmina Bogdanovic-Jovanovic ◽  
Dragica Milenkovic ◽  
Zivan Spasic ◽  
Dragan Svrkota
Keyword(s):  
Air Temperature ◽  
Axial Flow ◽  
Low Pressure ◽  
Operating Conditions ◽  
Empirical Formulas ◽  
Hot Air ◽  
Air Temperatures ◽  
The Common ◽  
Law Of Similarity ◽  
Temperature And Pressure

Performance characteristics of fans are generally provided for the normal temperature and pressure conditions (tI = 20?C, pI = 101.325 kPa, ? I = 1.2 kg/m3). Very often, fans operate in different air conditions, occasionally at different air temperatures. In these cases, equations obtained by the law of similarity are usually used for recalculation of the fan operating parameters. Increasing the inlet air temperature causes a decrease in the characteristic of Reynolds number, and may lead to efficiency lowering of the fan. There are also some empirical formulas for recalculation of fan efficiency, when operating at different air temperatures. In this paper, the common way for obtaining fan performance for different operating conditions (air temperature changing) is presented. The results, obtained by recalculation of fan parameters using a law of similarity, are compared to numerical simulation results of the axial-flow fan operating with different air temperatures. These results are compared with results obtained by some recommended empirical formulas, as well. This paperwork is limited to low-pressure and mid-pressure fans, which represents the majority of all fans used in practice, for different purposes.

scholarly journals Spatial and Temporal Distribution of Temperature, Relative Humidity and Air Velocity in a Parallel Milking Parlour During Summer Period

2015 ◽  
Vol 15 (2) ◽  
pp. 517-526 ◽  
Author(s):  
Piotr Herbut ◽  
Sabina Angrecka ◽  
Grzegorz Nawalany ◽  
Krzysztof Adamczyk
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Ventilation System ◽  
Temporal Distribution ◽  
Operating Conditions ◽  
Air Velocity ◽  
Summer Period ◽  
Air Movement ◽  
Air Stream ◽  
Relative Air Humidity

Abstract The research aimed at determining the most significant parameters affecting the microclimate of milking parlours, such as temperature, relative humidity and air movement in a parallel milking parlour in real operating conditions. The research was conducted in the summer period, when the risk of heat stress in cattle is higher. To check welfare of cows during milking, days with air temperature >25°C and days with temperature equal or lower than 25°C were analysed. Observation and analysis were performed for air flow in milking parlour, range of supplied air stream and how air movement affects cattle. It was observed that the irregular distribution of air movement led to the development of diverse air velocity in different zones of the milking parlour (0.2-9.0 m∙s-1). As a consequence, the conditions inside the barn were not homogenous for all the cattle. A significant effect of the cows and external air temperature (which depends indirectly on orientation of the milking parlour relative to cardinal directions) on temperature increase (approx 6°C) was concluded, with relative air humidity at the level of 85-90%, during the milking, which led to systematic decrease of microclimatic comfort for cattle. Based on the conducted research, it was concluded that the design of ventilation systems in parallel milking parlours should be preceded by increased research not only on ventilation system efficiency but also on the distribution of flow ventilated air.

scholarly journals Thermo-Economic Assessment of a Gas Microturbine-Absorption Chiller Trigeneration System under Different Compressor Inlet Air Temperatures

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4643 ◽  
Author(s):  
Guillermo Valencia Ochoa ◽  
Carlos Acevedo Peñaloza ◽  
Jorge Duarte Forero
Keyword(s):  
Air Temperature ◽  
Economic Assessment ◽  
Economic Factor ◽  
Operating Conditions ◽  
Exergy Destruction ◽  
Absorption Refrigeration ◽  
Steam Generation ◽  
Cost Difference ◽  
Air Temperatures ◽  
Compressor Inlet

This manuscript presents a thermo-economic analysis for a trigeneration system integrated by an absorption refrigeration chiller, a gas microturbine, and the heat recovery steam generation subsystem. The effect of the compressor inlet air temperature on the thermo-economic performance of the trigeneration system was studied and analyzed in detail based on a validated model. Then, we determined the critical operating conditions for which the trigeneration system presents the greatest exergy destruction, producing an increase in the costs associated with loss of exergy, relative costs, and operation and maintenance costs. The results also show that the combustion chamber of the gas microturbine is the component with the greatest exergy destruction (29.24%), followed by the generator of the absorption refrigeration chiller (26.25%). In addition, the compressor inlet air temperature increases from 305.15 K to 315.15 K, causing a decrease in the relative cost difference of the evaporator (21.63%). Likewise, the exergo-economic factor in the heat exchanger and generator presented an increase of 6.53% and 2.84%, respectively.

scholarly journals AntAir: satellite-derived 1 km daily Antarctic air temperatures since 2003

2019 ◽  
Author(s):  
Hanna Meyer ◽  
Marwan Katurji ◽  
Florian Detsch ◽  
Fraser Morgan ◽  
Thomas Nauss ◽  
...  
Keyword(s):  
Temporal Resolution ◽  
Air Temperature ◽  
Land Surface ◽  
Environmental Science ◽  
Spatial Location ◽  
Machine Learning Algorithms ◽  
Air Temperatures ◽  
Wide Range ◽  
Spatio Temporal ◽  
Patterns And Processes

Abstract. Air temperature is an important baseline parameter for terrestrial Antarctica in the context of patterns and processes in climatology, hydrology or ecology. There are still large uncertainties on how the Antarctic system responds to spatio-temporal variability of temperature. This can partly be attributed to the lack of high resolution datasets. In this paper, we present AntAir, a new dataset of gridded air temperatures in 1 km spatial and daily temporal resolution that is available since 2003. AntAir was created by modelling daily air temperature from MODIS land surface temperature using machine learning algorithms. Data from 70 weather stations was used as a reference. Daily temperatures could be estimated with a R2 of 0.91 and a RMSE of 5.07 °C validated on independent years. The performance to estimate the time series of a new spatial location was R2 = 0.78 and RMSE = 5.83 °C. Hence the high spatial and temporal resolution of the dataset as well as the high accuracy make AntAir an important baseline dataset for a wide range of applications in environmental science of Antarctica. The dataset is available at https://doi.pangaea.de/10.1594/PANGAEA.902166 (daily, Meyer et al., 2019a) and https://doi.pangaea.de/10.1594/PANGAEA.902193 (monthly, Meyer et al., 2019b).

Sign in / Sign up

Export Citation Format

Share Document