Outflow laminar

In-cloud overpressure is dependent on outflow velocity, orifice diameter, and the fuel s laminar burning velocity. 

In turbulent flow, the edge effect due to the shape of the support rod is quite significant as shown in Fig. 6. The data obtained with a support rod of equal radius agree with the theoretical prediction of Eq. (52). The point of transition with this geometry occurs at Re = 40000. However, the use of a larger radius support rod arbitrarily introduces an outflowing radial stream at the equator. The radial stream reduces the stability of the boundary layer, and the transition from laminar to turbulent flow occurs earlier at Re = 15000. Thus, the turbulent mass transfer data with the larger radius support rod deviate considerably from the theoretical prediction of Eq. (52) a least square fit of the data results in a 0.092 Re0 67 dependence for... 

The simplest flow systems, namely laminar flow tubes operated at atmospheric pressure, were used in some of the earliest chemical studies of hydrocarbon oxidation [4, 28, 53]. In this type of application, pre-mixed gaseous fuel and air flowed through a heated tube and the products were collected at the outflow under stationary-state conditions. Product compositions were analyzed and extents of reaction were deduced. Even in these earliest studies, the possibility of temperature changes owing to exothermic oxidation were noted and in some cases mildly explosive reaction , probably cool-flames, were detected [4]. 

If. eq. (4) is not satisfied for step-up and step-down tracer tests, then the proper distribution functions have not been obtained by the tracer test. The cause might be either that the system was not at steady state, or that the tracer did not behave perfectly and underwent a nonlinear process within the system. Another requirement for establishing the F(t) curve correctly from tracer step-up or step-down experiments, which is particularly important for systems with laminar flow, is that tracer must be introduced proportionally to flow (flow tagging) and that its mixing cup concentration must be monitored at,the outflow (18-21). 

Through simulation two cases are investigated laminar and turbulent outflow. In the case of laminar outflow the exponent x is approximately equal to one, in the case of turbulent outflow it is approximately equal to two. The values of y are chosen such that the flow at the start of both processes is the same. The results are shown in Fig. 2.7. 

Initially the decrease in level is the same, but the tank with turbulent outflow empties faster. The outflow in case of turbulent flow decreases linearly with time. Especially the time to empty the tanks is different. In case of turbulent flow this time is two minutes, in case of laminar outflow this time is larger than 5 minutes. 

Fig. 2.7. Simulation results of emptying liquid tank with laminar and turbulent outflow. For values 0 < jc < 1, the solution is not an exponential function. Substitution of...

Suppose, the outflow (Fig. 10.3) depends on the level (laminar outflow), according to ... 

Figure 10.17 shows two identical tanks with laminar free outflow. There is no feedback from the second tank to the first one. 

Figure 10.18 shows two similar tanks with laminar free outflow. They are positioned in such a way that there is feedback from the second tank to the first one. The level in the second tank has an impact on the level in the first tank. The dynamic equations can be written as ... 

The exact shape of the velocity profile in the outflow of an impeller does not depend solely on the impeller. It is also affected by such variables as the impeller Reynolds number, impeller off-bottom distance C/T, and impeller diameter D/T. If the flow is fully turbulent (i.e.. Re > Kf ), the impeller outflow profiles are typically independent of Reynolds number. If the flow is flansitional or laminar, however, care should be taken so that the velocity profiles used were either measured at a similar Reynolds number, or that the prescribed velocities are being interpolated from data sets measured over a range of Reynolds numbers. Similarly, for impeller off-bottom clearance and diameter, if data for various C/T and D/T values are available, interpolations can be used to obtain the prescribed velocities for the actual conditions. 

The value of this variable is set to zero at the outflow boundary and its values represent the time it will take fluid at any location to travel to the outflow boundary given the velocity field u. Multiplying this variable by 4-q/(jzD ), the flow rate divided by the pipe cross sectional area, produces a variable that can be used to indicate where each drawn litre starts from. The starting point of the water that contributes to the nth litre drawn from the pipes is identified by the positions where the value of P = AqContour plots of P for the four combinations of 12 mm or 18 mm diameter pipes and plug or laminar flow are contained in Figure 3.1 to 3.4. Each shade in those images represents a different litre. 

Measurements of stream diffusion flame length have been performed by many authors. It is known that the relative length of the laminar flame is in proportion to Reynolds number of the outflow stream [22]. When the Reynolds number approaches its critical value Re 2,300, the flame becomes turbulent [23]. 

For the micro-scale simulations of flow around textile fibers, Sobera et al. [8] simulated a 3-dimensional flow domain, with a virtual textile plane halfway and parallel to the inflow and outflow boundary of the domain. The inflow boundary conditions (laminarized flow in the vicinity of the textile) are obtained from the meso-scale DNS simulations. Periodic boundary conditions are applied to the edges of the virtual textile. Considering the textile as a 2-dimensional array of cylinders, at a mutual half distance, porosity is given by ... 

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