The dispersion relation in Eq. (5.1) gives a linear dispersion relation of the KHI of two inviscid fluids in the influence of oblique electric field. The nature of shows the fluctuation of the amplitude of the perturbed interface and will, therefore, govern the stability behavior of the electrohydrodynamic surface waves. Therefore, the necessary criterion of the stability is that must be real, which means a positive discriminate of the quadratic equation (5.1). It follows that the stability criterion requires: (5.2) The stability criterion (5.2) shows that the oblique electric field intensity has a stabilizing effect if and conversely if .
The computational results indicate that heat transfer is strongly affected by Reynolds and Richardson numbers. As the value of Ri increases, there occurs a transition from forced convection to buoyancy dominated flow at Ri >1. A detailed analysis of flow pattern shows that natural or forced convection is based on the parameter Ri. Key words: Richardson number (Ri), Reynolds number (Re), partial differential equations (pdes), finite difference method (FDM), The heated vertical wall. I.INTRODUCTION AND LITERATURE REVIEW 1.1 Background of study Thermal buoyancy forces play a significant role in forced convection heat transfer when the flow velocity is relatively small and the temperature difference between the surface and the free stream is relatively large.
al, 2014). El Sherry et. al (2014) concludes that flow velocity plays an important role in regulating sperm rheotactic behaviour. El Sherry et. al (2014) suggests that mechanical effects may exist through mechanosensing ion channels (MSCs) due to fluid shear stress increasing on the membrane of sperm head with an increase in the liquid velocity.
And also some of the literatures were unable to make any conclusions about friction factor for such type of problems. The project work conducted focused on study of variation in heat transfer and friction factor in flow through cascaded spiral inner tube heat exchanger. The results obtained from
In general, the greater the temperature difference, the better the driving force of the steam. Additionally, having a high temperature difference will increases the flow rate of the liquid and vapour within the tube. This increase in flow rate causes higher turbulence which results in an increase of the heat transfer coefficient. However, the overall temperature difference has to be within the range of boiling points of the two components as it could affect the quality and the purity of the products. Although rising film evaporator have many advantages for example rising film evaporator has low residence time this means that it allows the use of high temperature and still produce products of high quality irrespective of whether the product is heat sensitive, but it has low efficiency compared to other evaporators.
The overall pump curves for pumps in series and pumps in parallel were obtained and compared to theory and from this it was concluded that when two identical pumps are connected in series the overall head is doubled at a constant flow rate. Also, when two identical pumps are connected in parallel the flow rate at a particular head is doubled. The phenomenon of cavitation was demonstrated and the effects of fluid flow rate and suction static head on cavitation were observed. It was concluded that as the fluid flow rate decreased, more bubbles appeared and thus the chances of cavitation increased. Furthermore, because of the decrease in inlet pressure due to a decrease in flow rate, the suction static head also decreased.
In case of a viscous material response will be an out-of-phase strain wave. This phase difference in the applied and measured response frequency at extremes will be such that for a Newtonian liquid the phase angle will be 90 degrees and that for a perfectly elastic solid will be 0 degrees. Phase angle thus for a viscoelastic material will be in between 0 and 90 degrees
They analyse variations of exergy transfer effectiveness with number of transfer units (NTU), with the ratio of the heat capacity of cold fluid to that of hot fluid (Cc/Ch) and with finite pressure drops. They note that there is not an optimal combination of NTU and Cc/Ch for maximising exergy transfer effectiveness. They donot elaborate on the effects of temperature variations.Johannessen et al. (2002) examine temperature profiles and local entropy productionprofiles in heat exchangers. They show that the standard counter-current heat exchanger is the best first approximation to optimal heat exchange conditions in practice, as it has, mqualitatively the same properties as the optimal solutions presented in their study; when the temperature difference Th – Tc between the hot and the cold fluids is approximately constant.
It is generally accepted that swelling of granules increase the viscosity during heating of starch in water. Breakdown refers the rigidity/fragility of the swollen granules. The properties of the swollen granules and the soluble materials leached out from the granules are cooperatively ruling the viscosity parameters during pasting (Doublier et al., 1987). Growing demand of starch has created interest in searching the non-conventional starch sources and buckwheat (Fagopyrum) is a promising new starch source as it produces starch with diverse
This was expected because as the cold water flow rate increased, more heat transfer was occurring throughout the heat exchanger between the hot and cold streams. The plate heat exchanger was observed to have much higher overall heat transfer coefficient values than either the shell-and-tube or the double pipe. This was attributed to the plate heat exchanger having larger temperature differences from the increased outlet cold stream and the decreased outlet hot stream compared to the other heat exchangers. Thereby, the overall heat transfer coefficient significantly increased for the plate heat exchanger. The shell-and-tube and the double pipe heat exchangers did not have as large a difference in temperature change, thereby resulting in similar overall heat transfer coefficient values.