The counter flow is more efficiency at exchanging the heat energy due to its larger average temperature difference. Another type of heat exchanger is known as shell and tubes configuration. Tube bundle is the sub component in this type of configuration. The baffled is installed to support the bundle tube, induce the turbulence
THEORY Evaporation is the removal of solvent as vapour from a solution. There are four factors that affect evaporation, the area of exposed water surface the larger the area, the greater the loss; the temperature of the water and air above it a higher temperature increases loss; the movement of air above the water surface a greater movement carries off more vapour; and the relative humidity dry air absorbs moisture more readily than moist air. According to the kinetic theory of evaporation, molecules of water are in a constant state of random motion, colliding with one another, and rebounding. In the liquid state, these molecules are held in balance bycohesive force; however, some molecules possess sufficient kinetic energy to overcome this cohesive force and break free from the water surface, thus forming gaseous molecules. The fundamental law of evaporation is credited to Dalton (87).
Stage 2: Now these molten or semimolten droplets are accelerated to high velocities toward the substrate. This provides momentum to the stream of particles. Stage 3: The molten or semimolten particles impact the substrate to form the coating. Deposition occurs due to successive impacts of particles. Deposition can be mechanically integrated or metallurgically
As shown in fig the incoming stream is subsonic, and the molecules far upstream of the cylinder get the information about the presence of the body through the signals which travel with the speed, well in advance before reaching the cylinder. Therefore, the molecules orient themselves in order to flow around the cylinder, But when incoming stream is supersonic the molecules travel faster than the signals and there is no possibility that they will be informed of the presence of the body, before they reach the cylinder. Also the reflected signals from the face of the cylinder tend to coalesce a short distance ahead of the body. Their coalescence forms a thin compression front called shock wave, as shown in fig below-
These factors together contribute to band broadening. Eddy diffusion the A term, is caused by difference in the solute flow path and is mainly unaffected by the flow rate. This factor arises due to multiplicity of pathways for a gas flowing through the column. Solute molecules will take different paths through the stationary phase at random. This will cause broadening of the solute band, because different paths are of different
Temperature: Corrosion depends on the temperature of the environment. The rate of corrosion increases with increase in temperature. ii. Moisture: Corrosion depends on the amount of moisture present in the environment The rate of corrosion increases with increase in the moisture or humidity iii. pH Value: Corrosion depends on the pH value of the surrounding environment.
Elevated temperatures cause the water in the fluids to evaporate, which causes the viscosity to rise. Occasionally, distilled water will have to be added to the system to make the fluid balanced. Whenever these fluids are used, several system components must be checked for compatibility, including pumps, filters, plumbing and many more. Water-based fluids can be more expensive than conventional petroleum-based fluids and have other disadvantages (for example, lower wear resistance) that must be weighed against the advantage of
The particles in these fluids can move from place to place. Convection occurs when particles with a lot of heat energy in a liquid or gas move and take the place of particles with less heat energy. Heat energy is transferred from hot places to cooler places by convection. The particles in liquids and gases move faster when they are heated than they do when they are cold. As a result, the particles take up more volume.
By increasing the impact velocity, this enhances the heat flux from the surface of the material because of wider spread of the droplet. From the study it is found that, for a fixed flow of the water (laminar or turbulent identified using Reynold Number), cooling effectiveness increase with Weber