3.2 Effect of Pressure and Equivalence Ratio Fig. 3 (1) - (3) give the effects of pressure and equivalence ratio on ignition delay times of DME/air, n-butane/air and 50%DME50%n-butane/air binary fuel. Note that for all mixtures, ignition delay times decreased with the increase of pressure, meaning that the increase of pressure can promote fuel ignition in current conditions. This is mostly due to the increased fuel concentration and enhanced molecule collision probability at elevated pressures. The influences of equivalence ratio on the ignition delays of DME/air and n-butane/air mixtures were investigated at pressures of 2 and 10 atm.
Intake charge air densities shown in the fig are hard to obtain without charge air-cooling. The effect of charge air- cooling on density ratio is a function of the effectiveness of the charge air cooler and the pressure loss from compressor discharge to intake manifold. The effectiveness is defined as the ratio of temperature drop of charge air across the cooler to maximum temperature potential available for cooling. E = 12 T3: Intake manifold temperature T2: Compressor discharge temperature T1: Ambient temperature, which is assumed to be the same as compressor inlet temperature medium, above equation directly applies. In cases where water is used as intermediate cooling medium, the overall effectiveness is composed of the charge air cooling effectiveness and the corresponding radiator effectiveness.
Raw gas compression, the process gas is further cooled. When the compressed gas is sent to the CO2 separator this is used in order to recover CO2. In the cold box section the operating temperature is low. The last step is the fractionation, in which it separates the product from the unreacted propane which is recycled. CATOFIN Process The overall selectivity of the process is greater than 86mol% of propane to propylene.
Bottom Chamber liquid: Ethanol has a very low boiling point. When you heat the bottom chamber with your hand, the liquid molecules in the hand boiler increase in kinetic energy (increased temperature); the liquid expands. This rise in temperature causes the liquid to start to evaporate. Because there is some evaporation, but no condensation, the equilibrium is ruined in the hand boiler until the evaporated molecules lose kinetic energy and become liquid again (cool off). Bottom Chamber gas: When you apply heat to the bottom chamber, the gas increases in pressure because of the evaporated molecules.
The reference state is defined to be the most stable state for a particular element at a specified temperature and 1 bar (can often be assumed to be 1 atm). The most common reference state used is 298 K and 1 bar (also known as standard conditions). For example, the standard enthalpy change of formation of oxygen gas at 298 K and 1 bar is zero. (N.B. : standard conditions here are not the same as STP!)
INCANDESCENT LAMP Incandescent lamp also known as temperature radiator or general lighting service lamp (GLPS) is a temperature dependent source. When electric current flow through fine metallic wire known as filament, its temperature increases. When the temperature is low it emits heat energy but as soon as temperature increases from certain level it emits visible radiations along with heat energy. The filament is enclosed in glass bulb prevents oxygen of the air from reaching the hot filament, which would otherwise be rapidly oxidized and destroyed. Filament should have following properties: • Melting point of material should be high • Temperature coefficient must be low • Highly resistive • Should have good mechanical strength to withstand mechanical damages • Should be ductile After the invention of incandescent lamp number of materials were used as filament like carbon, osmium, tantalum but they failed since they didn’t have the properties that good
• The Gases are ideal. • Fuel cell is fed with Hydrogen and air. • The ratio of pressure between the inside and outside of the electrode channel is large enough to assume chocked flow. Fig. 2 V-I Characteristics Fig 2 shows the V-I Characteristic of PEM fuel cell which operate in three potential region.in PEM fuel cell the voltage across the cell is related with low current and it is due to activation loss inside cell; output voltage at the end of the curve will drop sharply as the load current increases.
TABLE OF CONTENTS Introduction 1.0 Methodology 2.0 Results 3.0 Theoretical Results 4.0 Discussion 5.0 Conclusion 6.0 References 7.0 i Heat transfer from a flat plate in parallel flow DavidMcLoughlin 15553097 Introduction Heat travels in three forms; conduction, convection and radiation. In this experiment the process of convection and radiation was investigated. Convection occurs due to the fact that when a gas is heated its pressure will remain the same and its density drops. Therefore, in a system the warmest gas will always travel to the “top” of the system where density is at its lowest. Heat travels through this form by creating a cycle of cold air replacing the risen warm air.
High cetane number fuels generally cause lower combustion noise, improved control of combustion, resulting in increased engine efficiency and power output. CN = (u40 + 17.8) 1587.9/ ρ40 Where; u40 is the Kinematic viscosity at 40°C, mm2/sec ρ40 is the density of the fuel at 40°C, Kg/ m3 Flash Point The flash point is the temperature at which the rising off the surface of the heated oil will ignite with a flash of very short duration when a flame is passed over the surface. When the oil is heated to higher temperature, it will ignite and burn with a steady flame at the surface. The
Vapor-compression refrigeration 2. Vapor-absorption refrigeration 1.1.1 Vapour Compression Cycle: The thermodynamics of the cycle can be analyzed on a diagram as shown. In this cycle, a circulating refrigerant such as Freon enters the compressor as a vapor. From point 1 to point 2, the vapor is compressed at constant entropy and exits the compressor as a vapor at a higher temperature, but still below the vapor pressure at that temperature. From point 2 to point 3 and on to point 4, the vapor travels through the condenser which cools the vapor until it starts condensing, and then condenses the vapor into a liquid by removing additional heat at constant pressure and temperature.