What is superficial velocity in fluidization?
Superficial velocity (or superficial flow velocity), in engineering of multiphase flows and flows in porous media, is a hypothetical (artificial) flow velocity calculated as if the given phase or fluid were the only one flowing or present in a given cross sectional area.
What is fluidization velocity?
2.1 Minimum fluidization velocity calculation. This is generally defined as minimum superficial velocity at which the drag force and the upward buoyant force due to the fluid is balanced by the weight of the particles illustrated in Figure 3.
How do you calculate fluidization?
Kozeny-Carman gave the formula of calculation of the minimum fluidization velocity for a very small particle size with the Remf < 10 in Eq. (14) described in Yates [16]. For spherical particles or sphericity equivalent, the bed voidage of the minimum fluidization εmf = 0.4 ÷ 0.45.
How do you calculate the velocity of a gas pipe?
The gas velocity, V, can be calculated from Page 14 13 V = Q/A = Q/(πD2/4) = 60/[π(1)2/4] = 76.4 ft/sec. Substituting values into Re = DVρ/μ gives: Re = (1)(76.4)(0.05486)/(2.45 x 10-7), or Re = 1.70 x 107. The Reynolds Number is much greater than 4000, so the flow is turbulent.
How do you calculate fluidization velocity in a fludized bed?
Typical fludized bed scheme ( u. f. : fluid velocity, ufm: minimum fluidization velocity). The expanded bed height is: (79)Z f = Z o 1 − ε 1 − εf. The minimum fluidization velocity can be calculated if the pressure drop in a fluidized bed is set equal to the pressure drop in a fixed bed:
How do you find minimum fluidization velocity?
The minimum fluidization velocity is determined empirically by the intersection of the pressure drop versus the superficial velocity curve and the pressure drop equals the weight of the bed line, as illustrated in Fig. 5.2. At minimum fluidization the velocity of the solids is taken to be the velocity in the packed bed region, that is, zero.
What is the pressure drop across the bed during fluidization?
At minimum fluidization, pressure drop across bed is balanced by effective weight of the particle. Beyond maximum superficial velocity, particles will be carried away by the gas and will leave at the bed exit.
What is the relationship between fluidization velocity and pressure?
Equation (5.16)shows that at high pressures the minimum fluidization velocity is lower than at low pressures because of the higher fluid density at high pressures. View chapterPurchase book