Alifia N Fadila
2001541831
Questions:
1. What are the applications of spray drying in the food industry?
2. Why the single- droplet spray drying was created?
3. There are 5 dimensionless number discussed in that paper, please mention them, and
their definition.
4. Which numerical model fits the best in this research?
5. What would be the limitation of this research?
Answers:
1. The applications of spray drying in food industry are usually in milk industry to create
milk powder. Nowadays, spray drying is widely used for manufacturing, e.g., milk
powder, whey powder, infant formula, lactose powder, and maltodextrin due to its
advantages.
2. Single-droplet spray drying are created to find the optimum drying condition for a
certain product. Usually, it is difficult to find the optimal drying condition using only
spray drying. The single-droplet drying has major advantage to determine the drying
kinetics under different drying conditions.
3.
Reynolds number is a dimensionless value that measures the ratio of inertial
forces to viscous forces and descibes the degree of laminar or turbulent flow.
L
Kf = 4f f = 16 Re (Reynold’s number for laminar flow). Systems that
dh
operate at the same Reynolds number will have the same flow characteristics
even if the fluid, speed and characteristic lengths vary.
The Prandtl Number is a dimensionless number approximating the ratio
of momentum diffusivity (kinematic viscosity) to thermal diffusivity - and can be
expressed as
Pr = v / α
where
Pr = Prandtl's number
v = momentum diffusivity (m2/s)
α = thermal diffusivity (m 2/s) Nusselt number defined as the ratio of convective
to conductive heat transfer across a boundary surface, predicts flow patterns. In
this context, convection includes both advection and diffusion. The conductive
component is measured under the same conditions as the heat convection but
with a (hypothetically) stagnant (or motionless) fluid.
Nusselt number, Nu, is the dimensionless parameter characterizing convective
heat transfer. It is defined as
where α is convective heat transfer coefficient, L is representative dimension
(e.g., diameter for pipes), and λ is the thermal conductivity of the fluid. Nusselt
number is a measure of the ratio between heat transfer by convection (α) and
heat transfer by conduction alone (λ/L).
2001541831
Questions:
1. What are the applications of spray drying in the food industry?
2. Why the single- droplet spray drying was created?
3. There are 5 dimensionless number discussed in that paper, please mention them, and
their definition.
4. Which numerical model fits the best in this research?
5. What would be the limitation of this research?
Answers:
1. The applications of spray drying in food industry are usually in milk industry to create
milk powder. Nowadays, spray drying is widely used for manufacturing, e.g., milk
powder, whey powder, infant formula, lactose powder, and maltodextrin due to its
advantages.
2. Single-droplet spray drying are created to find the optimum drying condition for a
certain product. Usually, it is difficult to find the optimal drying condition using only
spray drying. The single-droplet drying has major advantage to determine the drying
kinetics under different drying conditions.
3.
Reynolds number is a dimensionless value that measures the ratio of inertial
forces to viscous forces and descibes the degree of laminar or turbulent flow.
L
Kf = 4f f = 16 Re (Reynold’s number for laminar flow). Systems that
dh
operate at the same Reynolds number will have the same flow characteristics
even if the fluid, speed and characteristic lengths vary.
The Prandtl Number is a dimensionless number approximating the ratio
of momentum diffusivity (kinematic viscosity) to thermal diffusivity - and can be
expressed as
Pr = v / α
where
Pr = Prandtl's number
v = momentum diffusivity (m2/s)
α = thermal diffusivity (m 2/s) Nusselt number defined as the ratio of convective
to conductive heat transfer across a boundary surface, predicts flow patterns. In
this context, convection includes both advection and diffusion. The conductive
component is measured under the same conditions as the heat convection but
with a (hypothetically) stagnant (or motionless) fluid.
Nusselt number, Nu, is the dimensionless parameter characterizing convective
heat transfer. It is defined as
where α is convective heat transfer coefficient, L is representative dimension
(e.g., diameter for pipes), and λ is the thermal conductivity of the fluid. Nusselt
number is a measure of the ratio between heat transfer by convection (α) and
heat transfer by conduction alone (λ/L).
