China
Africa
Explore chapters and articles related to this topic
Prime Movers
Published in A.J. Pansini, K.D. Smalling, Guide to Electric Power Generation, 2020
Except for small gasoline powered engines that are cooled by an air stream flowing past the engine, practically all other internal combustion engines are cooled by water, liquid chemical compounds (that may also be rust preventatives), or a combination of the two. The coolant is circulated by pump through jackets surrounding the cylinders. Heat is extracted from the coolant by “radiators” through which ambient air is blown by means of a fan; for larger engines, the coolant may be brought to outside cooling towers or heat exchangers in which water is circulated. More will be described later when discussing steam turbines.
Applications of Nanomaterials
Published in Rajendra Kumar Goyal, Nanomaterials and Nanocomposites, 2017
Radiator: A radiator is a type of heat exchanger used to transfer heat from the hot coolant that flows through it to the air blown through it by the fan. Most of the modern cars use aluminum radiators made by brazing thin aluminum fins to flattened aluminum tubes. The coolant flows from the inlet to the outlet through many tubes mounted in a parallel arrangement. The fins conduct the heat from the tubes and transfer it to the air flowing through the radiator. Nanofluids enable the potential to allow higher temperature coolants and higher heat rejection in the automotive engines. The higher temperature radiator could reduce the radiator size by ∼30%. This translates ∼10% fuel savings due to reduced aerodynamic drag and fluid pumping and fan requirements. A nanofluid based on water with 0.65 vol% Fe2O3 NPs enhances the heat transfer of ∼9% in comparison with pure water in a car radiator [2]. The use of nanofluids as coolants would allow smaller size and better positioning of the radiators. In addition, due to better efficiency of the nanofluids, coolant pumps could be shrunk and truck engines could be operated at higher temperatures, allowing for more horsepower while still meeting stringent emission standards. For example, the application of nanofluids in radiators could reduce its size up to 10%, which in turn saves ∼5% fuel. The use of nanofluid also reduces the coefficient of friction and wear rate of pumps and compressors, which leads to >6% fuel savings. It is envisaged that further improvement in nanofluids could save more energy in the future. The aluminum NPs with thin layer of alumina produce hydrogen by splitting water during the combustion process. In this case, the aluminum acts as a catalyst and the aluminum NPs serve to decompose the water to yield more hydrogen. It has been studied that the combustion of diesel fuel mixed with aqueous aluminum nanofluid increases the total combustion heat while decreasing the concentration of smoke and nitrous oxide in the exhaust emission from the diesel engine.
Experimental investigation on heat transfer parameters of an automotive car radiator using graphene/water-ethylene glycol coolant
Published in Journal of Dispersion Science and Technology, 2022
Radiator is a compact heat exchanger used to expel the excess heat generated in internal combustion engines by passing coolant through it. Augmenting the thermal efficiency for optimizing the size of radiators to minimize the vehicle weight. For the last few decades, experiments were conducted to enhance the heat transfer rate using several methodologies including different types of fins, engineered surface texturing, twisted tape inserts, micro channels. Although, most of the conventional methods for enhancing the cooling rate by the aforesaid methods have faced certain restraints. An alternative technique to augment the fluid thermal properties by mixing of small solid particles in the range of millimetre to micrometre in fluid. However, due to the abrasive nature, sedimentation, clogging of flow channels, associated higher pressure drop and corrosion of the component confines the usability of such fluids in heat transfer applications. Nanofluids are suspensions of nanoparticles in base fluids to augment the thermal properties.[1–9] In the course of recent decades, nanofluids had shown noteworthy improvement in thermo-physical properties prompts incredible potential to usage in industrial applications. Nanofluids are gradually used in different heat exchangers to lessen the energy consumption. Hence, synthesizing suitable nanofluids of improved thermal properties and higher thermal conductivity has become challenging. Most experimental studies had concentrated on the suspension stability of nanofluids with addition of gum tragochan, ammonium hydroxide, cetyl trimethyl ammonium bromide, sodium dodecyl sulfate, oleic acid and sodium dodecyl benzene sulfonate surfactants as well as controlling pH suspension leads to enhance the stability of nanofluid.[10–15]
Enhancing Cooling System of a Combustion Engine by Integrating with a Stirling Cycle
Published in Energy Engineering, 2019
Ehab Bani-Hani, Mamdouh El HajAssad, Mohammad Tawalbeh, Bashira Yousef, Ahmad Sedaghat
A car radiator is a type of heat exchangers, which is a thermodynamic system that utilizes heat transfer mechanisms to allow for the maximum degree of interchange of energy in the form of heat. Radiators are used in vehicles, buildings, electric generators, airplanes, and most mechanical systems where heat needs to be dissipated.
Heat dissipation characteristic in the intake grille and radiator of a fuel cell vehicle
Published in International Journal of Green Energy, 2020
Chengyuan Gong, Jun Shen, Yi Yu, Kaiqiang Wang, Zhengkai Tu
In addition, radiator is also an indispensable part of automobile cooling system. Most of the heat generated by the fuel cell is transferred to the cold air through the radiator, which means that the performance of radiator will greatly affect the heat transfer performance of the whole vehicle. Numerous studies were available in the literature on radiator (Guo et al. 2011; Wang et al. 2015a; Wang et al. 2016). A vehicle radiator has three components, an intake chamber, an outlet chamber and a heat exchanger core. Coolant flows through the tubes of the radiator, and heat is transferred through the tube walls and fins of the radiator to the air by conduction and convection. Zhang et al. (2018b) investigated underhood airflow features associated with radiator performance, including the front grille opening size and underhood passive aerodynamic devices. The results showed that combining a side-grille seal with a wide air-duct could improve the overall fuel economy. Seybold et al. (2016) investigated various optimization potentials for a radiator to reduce the coolant pressure drop without compromising either the heat transfer performance or the air pressure drop. The results showed that the spigot diameter and fillet radius have the largest impact on the coolant side pressure drop. Yadav and Singh (2011) performed a series of numerical parametric studies on an automotive radiator. The results showed that the cooling capacity and efficiency of the radiator are directly related to the inlet temperature and the mass flow rate of the coolant. Lee, Hur, and Kang (2014) proposed a method involving microscopic and semi-microscopic analysis to predict the heat transfer characteristics of a louver fin radiator. The results were in good agreement with experimental data and can be used to efficiently and accurately design a louver fin radiator in a realistic vehicle model. Tang et al. (2008) used the genetic algorithm to optimize the radiator structure, including the wave height, the distance between the fins, the length and width of the pipe, etc. The heat transfer area was reduced by 31.2% by optimization.