Investigation on the effect of reformer gas on availability terms and waste heat recovery from exhaust gases of an HCCI engine considering radiation heat transfer

2019 ◽  
Vol 42 (1) ◽  
Author(s):  
Elaheh Neshat ◽  
Mohsen Asghari
Keyword(s):  
Heat Transfer ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Radiation Heat Transfer ◽  
Radiation Heat ◽  
Exhaust Gases ◽  
Hcci Engine ◽  
Reformer Gas

Analysis of Waste Heat Recovery to Steel Scrap Preheating in an Enclosure Vessel

2004 ◽  
Vol 449-452 ◽  
pp. 329-332 ◽  
Author(s):  
T. Wang ◽  
Masahiro Kawakami ◽  
Kazuya Mori ◽  
S.H. Shahidan
Keyword(s):  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Radiation Heat Transfer ◽  
Three Dimensional ◽  
Casting Process ◽  
Steel Scrap ◽  
Radiation Heat ◽  
Continuous Casting Process ◽  
Factors Affecting

A method for preheating steel scraps using waste heat in a continuous casting process was proposed. Experiment and numerical analysis were carried out to examine the ability of scrap preheating and to determine the factors affecting the rise in scrap temperature. Coupled natural convection-radiation heat transfer was solved by three-dimensional FEM. The distance and the constant were found to influence the sample's temperature rise greatly. The overall Nusset number can be obtained as Nu0=(-0.33α*D*0.8+7.08)Ra0.15t*-1- 32.4D*-0.99α*-1.98 *-1.98

The Effect of Inlet Turbulence Intensity on Nano-Particulate Soot Formation in Kerosene-Fueled Combustors

2016 ◽  
Author(s):  
Masoud Darbandi ◽  
Majid Ghafourizadeh
Keyword(s):  
Heat Transfer ◽  
Turbulence Intensity ◽  
Soot Formation ◽  
Mixture Fraction ◽  
Radiation Heat Transfer ◽  
Transport Equations ◽  
Maximum Temperature ◽  
Radiation Heat ◽  
Exhaust Gases ◽  
Soot Aerosol

In this work, we numerically study the effects of turbulence intensity at the fuel and oxidizer stream inlets on the soot aerosol nano-particles formation in a kerosene fuel-based combustor. In this regard, we study the turbulence intensity effects specifically on the thermal performance and nano-particulate soot aerosol emissions. To construct our computer model, we simulate the soot formation and oxidation using the Polycyclic Aromatic Hydrocarbons PAHs-inception and the hydroxyl concept, respectively. Additionally, the soot nucleation process is described using the phenyl route, in which the soot inception is described based on the formations of two-ringed and three-ringed aromatics from acetylene, benzene, and phenyl radical. We use the two-equation soot model in which the soot mass fraction and the soot number density transport equations are solved considering the evolutionary process of soot nanoparticles, where all the nucleation, coagulation, surface growth, and oxidation phenomena are suitable considered in calculations. For the combustion modeling part, we benefit from the flamelets library, i.e., a lookup table, considering a detailed chemical kinetic mechanism consisting of 121 species and 2613 elementary reactions and solve the transport equations for the mean mixture fraction and its variance. We take into account the turbulence-chemistry interaction using the presumed-shape probability density functions PDFs. We apply the two-equation high-Reynolds-number k-ε turbulence model with round-jet corrections and suitable wall functions in performing our turbulence modeling. Solving the transport equations of turbulence kinetic energy and its dissipation rate, the turbulence closure problem can be resolved suitably. Furthermore, we take into account the radiation heat transfer of soot and gases assuming optically-thin flame, in which the radiation heat transfer of the most important radiating species is determined locally through the emissions. To evaluate our numerical solutions, we first solve an available well-documented experimental test, which provides the details of a kerosene-fueled turbulent nonpremixed flame. Then, we compare the achieved flame structure, i.e., the distributions of mean mixture fraction, temperature, and soot volume fraction, with those measured in the experiment. Next, we change the turbulence intensities of the incoming fuel and oxidizer streams gradually. So, we become able to evaluate the effects of different turbulence intensities on the achieved temperature and soot aerosol concentrations. Our results show that using moderate turbulence intensities at both fuel and oxidizer stream inlets would effectively increase the maximum temperature inside the combustor and this would reduce the exhaust gases temperature. It also reduces the concentrations of soot in the combustor and its emission to the exhaust gases effectively.

scholarly journals Economic and Exergo-Advance Analysis of a Waste Heat Recovery System Based on Regenerative Organic Rankine Cycle under Organic Fluids with Low Global Warming Potential

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1317 ◽  
Author(s):  
Guillermo Valencia Ochoa ◽  
Cesar Isaza-Roldan ◽  
Jorge Duarte Forero
Keyword(s):  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Exhaust Gases ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Heat Recovery System

The waste heat recovery system (WHRS) is a good alternative to provide a solution to the waste energy emanated in the exhaust gases of the internal combustion engine (ICE). Therefore, it is useful to carry out research to improve the thermal efficiency of the ICE through a WHRS based on the organic Rankine cycle (ORC), since this type of system takes advantage of the heat of the exhaust gases to generate electrical energy. The organic working fluid selection was developed according to environmental criteria, operational parameters, thermodynamic conditions of the gas engine, and investment costs. An economic analysis is presented for the systems operating with three selected working fluids: toluene, acetone, and heptane, considering the main costs involved in the design and operation of the thermal system. Furthermore, an exergo-advanced study is presented on the WHRS based on ORC integrated to the ICE, which is a Jenbacher JMS 612 GS-N of 2 MW power fueled with natural gas. This advanced exergetic analysis allowed us to know the opportunities for improvement of the equipment and the increase in the thermodynamic performance of the ICE. The results show that when using acetone as the organic working fluid, there is a greater tendency of improvement of endogenous character in Pump 2 of around 80%. When using heptane it was manifested that for the turbine there are near to 77% opportunities for improvement, and the use of toluene in the turbine gave a rate of improvement of 70%. Finally, some case studies are presented to study the effect of condensation temperature, the pinch point temperature in the evaporator, and the pressure ratio on the direct, indirect, and fixed investment costs, where the higher investment costs were presented with the acetone, and lower costs when using the toluene as working fluid.

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