scholarly journals A study of the dynamic flue-gas temperature and off-period mass flow rate of a residential gas-fired furnace

1979 ◽  
Author(s):  
Cheol Park

The two horrible conditions ahead of time than the organizers worldwide are to diminish the stack at the conventional fills and to reduce the continually developing basic spoiling. This test is proposed to discover probably the execution of the DI diesel motor at various loads when fuelled with mixes of palm methyl esters and diesel. The primers have been pushed on a completely utilized diesel motor without changes. Every one of the appraisals were consistent usa of america and outfitted toward dependable pace. The impact of moving weight develop to be assessed the volume that brake warm temperature ability, mass flow rate, brake one of a kind gas use and fumes gas temperature. Exploratory impacts show that at complete weight conditions, the B-20, B-40and B-60 mixes bring 33.23%, 32.81%, 32.39% and 31.ninety seven% higher brake heat usefulness than sole diesel freely. It wound up confirmed that the brake warmth ability of palm biodiesel is higher than that of diesel, and it is a delayed consequence of the oxygenated atom of biodiesel which acknowledges total ingesting of the biodiesel fuel. In addition the mass development rate of biodiesel is evidently superior to anything that of diesel fuel; it is through method for exact capacity of the calorific estimation of biodiesel is a ton parcels less appeared in one another way as far as diesel gas. At the reason for results obtained from this test utilizing palm biodiesel as a fuel is proposed for the utilized as a piece of a diesel motor with diesel mixes.


Volume 1 ◽  
2004 ◽  
Author(s):  
Mohammad Ameri ◽  
Hamidreza Shahbaziyan ◽  
Hadi Hosseinzadeh

Heat recovery steam generators (HRSG) are widely used in industrial processes and combined cycle power plants. The quantity and the state of the produced steam depend on the flue gas temperature and its mass flow rate. Two key factors, which affect those parameters, are the ambient temperature and the load of the gas turbines. The output power of the gas turbines degrades considerably in hot days of summer. The use of the inlet air cooling system to eliminate this problem is rapidly increasing. One of the effective methods is cooling the inlet air to the compressor by Evaporative Coolers. The purpose of this paper is to study the effects of the evaporative inlet air cooling system on the performance of a heat recovery boiler in a combined cycle power plant. The heat and mass balance of a typical HRSG and its components including the superheaters, evaporators and economizers were calculated. To analyze the effects of the changes in ambient temperature and the flue gas flow, a numerical software has been used. The results have shown that using the evaporative cooler will increase the flue gas mass flow rate to the HRSG. Nevertheless, the exhaust gas temperature control system holds this temperature almost constant. Also, the results show that the produced steam temperature remains almost constant. However, the steam mass flow rate increases. Therefore the output power of the steam turbine of the combined cycle will increase. The effect of the increase in the humidity ratio is shown to be insignificant. In fact, it has negligible effect on the produced steam flow rate and the sulfuric acid dew point.


2017 ◽  
Author(s):  
E. Rogdakis ◽  
P. Bitsikas ◽  
G. Dogkas

In the present work, a three dimensional (3D) Computational Fluid Dynamics (CFD) analysis is applied to a designed small compact regenerator with specific porosity and wire diameter. The regenerator was studied as a part of a Stirling Engine designed in a simple way. The gas temperature along the regenerator followed an approximately linear profile, while the metal temperature showed a small deviation during the engine cycle. The heat transfer coefficient between the gas and the matrix of the regenerator, along with the associate heat transferred were also derived. The heat exchanged in the regenerator is significantly higher to the respective heat in the engine’s heater and cooler. Additionally, the pressure drop and the related energy dissipation are studied. Their variation is largely dependent on both mass flow-rate and working gas velocity. The friction factor coefficient for the designed regenerator is correlated with Reynolds number and an equation of two variables is derived. Finally, the results of the CFD simulation are compared to those produced by a one-dimensional numerical model. These results include gas mass, mass flow-rate and Reynolds number, as well as the heat transferred between the gas and the regenerator matrix. Except for the case of the exchanged heat, the deviation between the two approaches is very small.


2013 ◽  
Vol 431 ◽  
pp. 137-150 ◽  
Author(s):  
A. Minotti ◽  
F. Cozzi ◽  
F. Capelli

Improvements in understanding how to design future mesocombustors, currently under rapid development in particular for propulsion, e.g., for UAVs, and as meso-electrical power generators, are mandatory. In view of this scenario and, to advances previous analysis carried out at ambient pressure by the authors, the numerical and experimental investigation of a 254 mm3swirling cylindrical mesocombustor, fed by methane/air at an equivalence ratio =0.7 and at 3 bar, has been performed. The combustion pressure has been chosen based on the values quoted in literature for centimeter sized gas turbine.Exhaust gas temperature and composition have been measured for several mass flow rates. A reduction in chemical efficiency is observed by increasing the input thermal power (i.e. the total mass flow rate) at fixed equivalence ratio due to the shorter gas residence time.The operative condition corresponding to high efficiency and smaller mass flow rate has been numerically investigated adopting the RANS k-ε approach, with finite rate chemistry kinetic mechanism (GRIMech 1.2, 32 species and 177 reactions) and the EDC turbulence-combustion coupling model.Gas temperature at the exhaust section and chemicalefficiency are predicted and compared with the corresponding experiment.Numerical and experimental results show to be in fair agreement, and the predicted chemical efficiency differs from the measured value of about 1 %. Despite the small size of the meso-combustor, it is possible to achieve a relatively high combustion efficiency, making it suitable for miniaturized power generation devices.The relatively high chemical efficiency is due to the relatively long average gas residence time and to a wide recirculation zone that provide heat and radicals to the flame, coupled with the fairly good mixing due to swirl motion and the impinging air/fuel jets.


Author(s):  
B. I. Ismail ◽  
R. Zhang ◽  
D. Ewing ◽  
J. S. Cotton ◽  
J.-S. Chang

A one-dimensional steady state model was developed to predict the heat transfer performance of a shell (liquid)-and-tube (gas) heat exchanger used as a cooling device for exhaust gas recirculation (EGR) application where there is a significant temperature drop across the device. The predictions of the model results were compared with experimental measurements and the trends were found to be in good agreement for most of the transitional and turbulent regimes. The results showed that the exit gas temperature increases with increasing gas mass flow rate at fixed gas inlet temperature and coolant flow rate. It was also found that the exit gas temperature was essentially independent of the coolant flow rate for the typical operating range but did depend on the coolant inlet temperature. It was observed that the pressure drop across the cooling device was not a strong function of the gas inlet temperature. The heat-transfer effectiveness of the cooling device was found to slightly depend on the gas mass flow rate and inlet gas temperature. A preliminary analysis showed that fouling in the EGR cooling device can have a significant effect on both the thermal and hydraulic performance of the cooling device.


2014 ◽  
Vol 18 (4) ◽  
pp. 1389-1397 ◽  
Author(s):  
M.A. Ehyaei

In this paper the transient modeling of HRSG (Heat recovery steam generator) in purging time was considered. In purging time, compressed air from the gas turbine was used to purge a combustible gas from HRSG. During this time; steam condensate was formed in the superheater stage which should be drained completely to avoid some problems such as deformation of superheaters. Because of this reason, estimation of drain formation is essential to avoid this problem. In this paper an energy model was provided and this model was solved by MATLsoftware. Average model error is about 5%. Results show that, during purge time, steam temperature was decreased from 502 (?C) (Superheater 2), 392 (?C) (Superheater1) and 266 (?C) (Evaporators 1&2) to 130 (?C), 130 (?C) and 220 (?C), respectively and also steam pressure was decreased from 52 (bar) to 23(bar) during purge time. At end of purge time, condensate formation was about 220 (l) when inlet gas temperature was equal to 100 (?C) and purge gas mass flow rate was equal to 386.86 (kg/s).


2015 ◽  
Vol 19 (1) ◽  
pp. 329-340
Author(s):  
Todor Janic ◽  
Sasa Igic ◽  
Nebojsa Dedovic ◽  
Darijan Pavlovic ◽  
Jan Turan ◽  
...  

This study reviews test results of the combustion of square soybean straw bales used as fuel in manually fed boiler with nominal thermal power of 120 kWth. The influence of the mass flow rate (180, 265, 350, 435, and 520 kg h-1) of inlet air and flue gas recirculation (0%, 16.5%, and 33%) fed to the boiler furnace was continuously monitored. Direct method was used for determination of the boiler thermal power. Correlation between boiler thermal power and bale residence time has been observed and simple empirical equation has been derived. General conclusions are as follows: the increase of the flow rate of inlet air passing through the boiler furnace results in decrease of the bale residence time and increase of the boiler thermal power. Share of the flue gas recirculation of 16.5% increases bale residence time and decreases average boiler thermal power in all regimes except in the regime with inlet air flow rate of 265 kg h-1. In regime with 0% flue gas recirculation boiler thermal power was higher than nominal in regimes with 435 and 520 kg h-1 inlet air flow rates. In regimes having inlet air mass flow rate of 350 kg h-1 boiler thermal power is equal to the nominal power of 120 kWth.


2013 ◽  
Vol 774-776 ◽  
pp. 383-392 ◽  
Author(s):  
Hong Cui Feng ◽  
Wei Zhong ◽  
Yan Ling Wu ◽  
Shui Guang Tong

Changes of inlet temperature, mass flow rate and composition of flue gas, or of water/steam pressure and temperature in heat recovery steam generator (HRSG), all will modify the amount of waste heat recovered from flue gas; this brings forward a desire for the optimization of the design of HRSG. For single pressure HRSGs with given structures and specified values of inlet temperature, mass flow rate and composition of flue gas, the steam mass flow rate and gas outlet temperature of the HRSG are analyzed as functions of several parameters. This analysis is based on the laws of thermodynamics, incorporated into the energy balance equations for the heat exchangers. Those parameters are superheated steam pressure and temperature, feedwater temperature and pinch point temperature difference. It was shown that the gas outlet temperature could be lowered by selecting appropriate water/steam parameters and pinch point temperature difference. While operating with the suggested parameters, the HRSG can generate more high-quality steam, a fact of great significance for waste heat recovery from wider ranges of sources for better energy conservation.


The two horrible conditions ahead of time than the organizers worldwide are to diminish the stack at the conventional fills and to reduce the continually developing basic spoiling. This test is proposed to discover probably the execution of the DI diesel motor at various loads when fuelled with mixes of palm methyl esters and diesel. The primers have been pushed on a completely utilized diesel motor without changes. Every one of the appraisals were consistent usa of america and outfitted toward dependable pace. The impact of moving weight develop to be assessed the volume that brake warm temperature ability, mass flow rate, brake one of a kind gas use and fumes gas temperature. Exploratory impacts show that at complete weight conditions, the B-20, B-40and B-60 mixes bring 33.23%, 32.81%, 32.39% and 31.ninety seven% higher brake heat usefulness than sole diesel freely. It wound up confirmed that the brake warmth ability of palm biodiesel is higher than that of diesel, and it is a delayed consequence of the oxygenated atom of biodiesel which acknowledges total ingesting of the biodiesel fuel. In addition the mass development rate of biodiesel is evidently superior to anything that of diesel fuel; it is through method for exact capacity of the calorific estimation of biodiesel is a ton parcels less appeared in one another way as far as diesel gas. At the reason for results obtained from this test utilizing palm biodiesel as a fuel is proposed for the utilized as a piece of a diesel motor with diesel mixes.


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