Exhaust Heat Recovery Unit Equipped With Nanofluid and Helical Tapes, a Solution for Cleaner Energy Production

2020 ◽  
Vol 142 (11) ◽  
Author(s):  
M. Sheikholeslami ◽  
A. Arabkoohsar ◽  
M. Jafaryar
Keyword(s):  
Nusselt Number ◽  
Heat Exchanger ◽  
Environmental Impacts ◽  
Flue Gas ◽  
Heat Recovery ◽  
Internal Combustion Engines ◽  
Waste Heat ◽  
Physical Parameters ◽  
Twisted Tape ◽  
Exhaust Heat

Abstract In internal combustion engines (ICE), a major part of the generated energy via burning the fuel is wasted. The cooling fluid controlling the temperature, the reclaimed hot gases for reducing the environmental impacts, and the hot combustion productions leaving the engine from the exhaust are the main origins of energy waste in such a machine. Waste heat recovery and flue gas condensation are the methods by which the overall efficiency of a thermal engine is enhanced, and its environmental impacts are mitigated. In this paper, the utilization of the exhaust waste energy of ICE by using a heat exchanger with nanofluid and helical tape, in order to augment the thermal performance of the engine and reduce its environmental impact, is investigated numerically. In this heat exchanger, the flue gas of the engine at high temperature and H2O-CuO nanofluid are considered as the primary and secondary working fluids, and the twisted tape makes the flow further disturbed so that a larger overall heat transfer coefficient is obtained. The finite volume method has been applied to scrutinize the impacts of Reynolds number as well as the twisting-tape turns number on the operation and performance of the tube. As such, suitable correlations for the prediction of some of the thermos-physical parameters of the problem (such as Nusselt number and Darcy factor) are extracted regarding the obtained data. The results of the study reveal that Nusselt number is higher for larger numbers of the tape turn and higher Reynolds numbers, while a lower friction factor is achieved as the number of the turns is reduced.

Heat Transfer and Pressure Drop Investigations of the Compact Exhaust Heat Exchanger With Twisted Tape Inserts for Automotive Waste Heat Utilization

2020 ◽  
Vol 13 (4) ◽  
Author(s):  
Dhruv Raj Karana ◽  
Rashmi Rekha Sahoo
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Internal Heat ◽  
Decisive Role ◽  
Twisted Tape ◽  
Twisted Tapes ◽  
Exhaust Heat

Abstract Thermoelectric-based waste heat recovery is a competent technique to reduce the exhaust emissions and fuel consumption of automobiles. Thermal and hydraulic characteristics of the exhaust heat exchanger plays a decisive role in the extent of waste heat recovery from the exhaust gas. In this study, the exhaust heat exchanger having twisted tape inserts is proposed to increase the internal heat transfer coefficient. The dimensionless Nusselt number and friction factor were evaluated experimentally for different designs of the twisted tapes. The experiments were performed for the Reynolds number in the range 2300–25000. The considered geometric parameters of the twisted rib explored were the pitch fraction, twist fraction, and slope. The obtained results were compared to reveal the best feasible design of the twisted tape. The maximum net thermohydraulic efficiency factor achieved for the system in the present analysis is 1.93. With the use of twisted tapes, the area of the exhaust heat exchanger can be greatly reduced for the same power output as flat geometry. This would help for the integration of the waste heat recovery with the engine, where the space available is very limited.

The Potential Danger of Fire in Gas Turbine Heat Exchangers

1969 ◽  
Author(s):  
C. F. McDonald
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Heat Exchangers ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Engine Operation ◽  
Exhaust Heat ◽  
The Subject ◽  
Gas Turbine Cycle

Increased emphasis is being placed on the regenerative gas turbine cycle, and the utilization of waste heat recovery systems, for improved thermal efficiency. For such systems there are modes of engine operation, where it is possible for a metal fire to occur in the exhaust heat exchanger. This paper is intended as an introduction to the subject, more from an engineering, than metallurgical standpoint, and includes a description of a series of simple tests to acquire an understanding of the problem for a particular application. Some engine operational procedures, and design features, aimed at minimizing the costly and dangerous occurrence of gas turbine heat exchanger fires, are briefly mentioned.

scholarly journals Improving the efficiency of heat recovery circuits of cogeneration plants with combustion of water-fuel emulsions

2020 ◽  
pp. 154-154 ◽  
Author(s):  
Victoria Kornienko ◽  
Mykola Radchenko ◽  
Roman Radchenko ◽  
Dmytro Konovalov ◽  
Andrii Andreev ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Power Plant ◽  
Heat Recovery ◽  
Internal Combustion Engines ◽  
Waste Heat ◽  
Dew Point ◽  
Exhaust Gas ◽  
Direct Flow ◽  
Exhaust Heat ◽  
Heating Surfaces

When using modern highly efficient internal combustion engines with lowered potential of exhaust heat the heat recovery systems receive increasing attention. The efficiency of combustion exhaust heat recovery at the low potential level can be enhanced by deep cooling the combustion products below a dew point temperature, which is practically the only possibility for reducing the temperature of boiler exhaust gas, while ensuring the reliability, environmental friendliness and economy of power plant. The aim of research is to investigate the influence of multiplicity of circulation and temperature difference at the exit of exhaust gas boiler heating surfaces, which values are varying as 20, 15, 10?C, on exhaust gas boiler characteristics. The calculations were performed to compare the constructive and thermal characteristics of the various waste heat recovery circuits and exhaust gas boiler of ship power plant. Their results showed that due to application of condensing heating surfaces in exhaust gas boiler the total heat capacity and steam capacity of exhaust gas boiler increases. The increase of exhaust gas boiler heat capacity is proportional to the growth of its overall dimensions. A direct-flow design of the boiler provides a significant increase in heat efficiency and decrease in dimensions. In addition, a direct-flow boiler circuit does not need steam separator, circulation pump, the capital cost of which is about half (or even more) of heating surface cost.

scholarly journals Design and Development of Innovative Protracted-Finned Counter Flow Heat Exchanger (PFCHE) for an Engine WHR and Its Impact on Exhaust Emissions

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2717 ◽  
Author(s):  
Rajesh Ravi ◽  
Senthilkumar Pachamuthu
Keyword(s):  
Heat Exchanger ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Gas Temperature ◽  
Counter Flow ◽  
Exhaust Heat ◽  
Recovery System ◽  
Heat Recovery System ◽  
Flow Heat

This article describes and evaluates an Organic Rankine Cycle (ORC) for waste heat recovery system both theoretically as well as experimentally. Based on the thermodynamic analysis of the exhaust gas temperature identified at different locations of the exhaust manifold of an engine, the double-pipe, internally–externally protruded, finned counter flow heat exchanger was innovatively designed and installed in diesel engine for exhaust waste heat recovery (WHR). The tests were conducted to find the performance of heat recovery system by varying the fin geometries of the heat exchanger. The effect of heat exchanger on emission parameters is investigated and presented in this work. The experimental results demonstrated that the amount of heat transfer rate, the effectiveness of heat exchange rand the brake thermal efficiency improved with an increase in length and number of the fins. A significant reduction was observed in all major emissions after the implementation of catalytic-coated, protracted finned counter flow heat exchanger. It also demonstrated the possibility of electric power production using steam turbo-electric-generator setup driven by the recovered exhaust heat energy.

Experimental Study of Natural Gas Combustion Flue Gas Waste Heat Recovery System Based on Direct Contact Heat Transfer and Absorption Heat Pump

2013 ◽  
Author(s):  
Xian Zhou ◽  
Hua Liu ◽  
Lin Fu ◽  
Shigang Zhang
Keyword(s):  
Heat Exchanger ◽  
Flue Gas ◽  
Direct Contact ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Contact Heat ◽  
Absorption Heat Pump ◽  
Return Water ◽  
Recovery System

Condensing boiler for flue gas waste heat recovery is widely used in industries. In order to gain a portion of the sensible heat and latent heat of the vapor in the flue gas, the flue gas is cooled by return water of district heating through a condensation heat exchanger which is located at the end of flue. At low ambient air temperature, some boilers utilize the air pre-heater, which makes air be heated before entering the boiler, and also recovers part of the waste heat of flue gas. However, there are some disadvantages for these technologies. For the former one, the low temperature of the return water is required while the utilization of flue gas heat for the latter one is very limited. A new flue gas condensing heat recovery system is developed, in which direct contact heat exchanger and absorption heat pump are integrated with the gas boiler to recover condensing heat, even the temperature of the return water is so low that the latent heat of vapor in the flue gas could not be recovered directly by the general condensing technologies. Direct contact condensation occurs when vapor in the flue gas contacts and condenses on cold liquid directly. Due to the absence of a solid boundary between the phases, transport processes at the phase interface are much more efficient and quite different from condensation phenomena on a solid surface. Additionally, the surface heat exchanger tends to be more bulky and expensive. In this study, an experimental platform of the new system is built, and a variety of experimental conditions are carried out. Through the analysis of the experimental data and operational state, the total thermal efficiency of the platform will be increased 3.9%, and the system is reliable enough to be popularized.

scholarly journals Gas-side fouling, erosion and corrosion of heat exchanger for middle and low temperature flue gas waste heat recovery

2016 ◽  
Vol 61 (17) ◽  
pp. 1858-1876 ◽  
Author(s):  
FeiLong WANG ◽  
SongZhen TANG ◽  
WenQuan TAO ◽  
YaLing HE ◽  
QinXin ZHAO
Keyword(s):  
Heat Exchanger ◽  
Low Temperature ◽  
Flue Gas ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat

Performance evaluation of metal-foam baffle exhaust heat exchanger for waste heat recovery

2020 ◽  
Vol 266 ◽  
pp. 114875 ◽  
Author(s):  
Tianyu Chen ◽  
Gequn Shu ◽  
Hua Tian ◽  
Tingting Zhao ◽  
Hongfei Zhang ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Heat Exchanger ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Metal Foam ◽  
Waste Heat ◽  
Exhaust Heat
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