No abstract

Every year there is a rise in energy demand due to the rapid development in industrializationand automotive sector, demand and depletion of fossil fuels, fuel price instabilities, diminished energysecurity, uncertainty in oil supply to the consuming nations, fuel import costs, increased harmfulenvironmental effects due to various pollutants are the main driving forces to search for new alternativefuels that are renewable, eco–friendly and harmless in nowadays. Most researchers have focused ondeveloping a wide range of renewable energies including oxygenated fuels, biofuels, fuel cell, and solarenergy technologies to reduce the consumption of fossil fuels and control the emission of greenhouse gasesto emit the atmosphere. The novel application in transportation and power generation sectors has showndevelopment in the past decades to ensure a low emission level, energy savings, and high performance andefficiency. A new research area grows rapidly which is called nanotechnologies are considered nowadaysone of the most recommended choices to solve the problem of the production and use of energy.Nanotechnology can be used to improve the efficiency and performance of both of conventional andrenewable resources and also fuels. Nanofuels consist of a nano–sized metal particle having size rangingfrom 1 to 100 nm is mixed inside the base fluid by means of ultrasonication process. The nano fuel additivehas a higher surface to volume ratio and act as a catalyst that results in enhanced characteristics of fuelsand oils which leads to enhanced performance and combustion characteristics of internal combustionengines. This review study investigates the effects of nanolubricant addition into lube oil on theperformance of spark ignition engines.

This review study was gathered from the results of various papers performed on the use ofdimethyl ether as a fuel or fuel additive in diesel engines. Several methods are applied for the reduction ofthe polluting emissions emitted from diesel engines. The first method for the reducing of hazardousemissions is improved the combustion by the modification of engine design and fuel injection system, butthis is expensive and time consuming process. The second method is the using of various exhaust gasdevices i.e. catalytic converters and diesel particulate filters. However, it is determined that the use of thesedevices affects diesel engine performance conversely. The last method to reduce the polluting emissionsand also improve the diesel engine performance is the using of renewable alternative fuels or various fueladditives. Among the various alternative fuels, dimethyl ether (DME) is the pioneer by reason of itsattractive fuel properties such as high cetane number and oxygen content. On the other hand, the physicaland chemical properties of the used fuel play the important role on the injection, ignition and combustioncharacteristics of internal combustion engines (ICEs). Moreover, outputs of ICEs i.e. performance, fuelconsumption and emissions are affected extensively from the ignition, injection and combustioncharacteristics. Therefore, it is essential that the results of studies performed on dimethyl ether are evaluatedtogether to support future researches and practice applications. Especially, this review study investigatesthe effects of using DME on the ignition characteristics.

The pumps are divided into two main groups as positive displacement namely volumetric pumps and dynamic i.e. centrifugal pumps. Volumetric pumps are generally used to transport hydraulic oils, while centrifugal pumps are used to transport clean or dirty water. Pumps are the tools that are used to move liquid fluids from one place to another in many areas like as cars, industry, construction sites, agriculture, and homes. Therefore, determination of the hydraulic pump’s characteristics under various working conditions, including manometric head, overall efficiency, specific speed, and net positive suction head, is crucial for development, operational limitations, and durability. Experimental investigation is a more realistic method, although it is possible to determine the hydraulic pump characteristics by means of mathematical methods. Therefore, an experimental investigation is performed for the determination of the centrifugal pump characteristics in this study by using an experimental setup. The findings indicate that the hydraulic power given to the water and the electrical power used by the pump both increase up to a particular flow rate and then decline. Additionally, it is found that manometric head of the pump falls even as the overall flow losses rise as the flow rate rises. On the other hand, overall efficiency of the pump enhances at the specific flow rate and then it reduces with the increased flow rate while specific speed of the pump varies about linearly. Moreover, it is finally noticed that the tested centrifugal pump works in cavitations at all flow rates.