584 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
Additionally, numerical models have been created to
predict and simulate bubble behavior in the dry dense
medium fluidized separation process. These models con-
sider various factors such as fluid dynamics, particle interac-
tions, and bubble characteristics to provide insights into the
mesoscale behavior of bubbles. By utilizing these numerical
models, researchers can optimize the parameters and condi-
tions of the separation process to enhance its efficiency and
effectiveness.
Furthermore, the regulation of the mesoscale structure
in the gas-solid separation fluidized bed has been a subject
of detailed investigation. This involves the introduction of
external energy to control and manipulate bubble behav-
ior. The introduction of external energy, such as mechanical
vibration or acoustic waves, can significantly influence the
behavior of gas bubbles in the fluidized bed. This external
energy input can induce the formation of smaller bubbles,
enhance bubble coalescence, and promote the fracturing of
larger bubbles into smaller ones. By carefully controlling
these external energy inputs, researchers can manipulate the
bubble dynamics within the fluidized bed and optimize the
separation efficiency.
MESOSCALE STRUCTURE
The dense medium fluidized bed, which is a gas-solid two-
phase flow system, is commonly studied in the field of bub-
bling fluidization. It comprises an emulsion phase, formed
by particle aggregation, and a bubble phase, formed by gas
aggregation. The movement of bubbles leads to nonlinear
changes in key parameters such as apparent density and
pressure drop of the bed over time and space. These bubble
movements not only impact the even distribution of dense
medium particles but also influence the segregation behav-
ior of coal particles based on density. Thus, reducing the
disturbances caused by bubbles is crucial for improving the
quality of fluidization and enhancing the density segrega-
tion of coal particles. From a fluidization perspective, the
presence of bubbles defines the gas-solid separation fluid-
ized bed as a complex system, characterized by multiple
scales, nonlinearity, and transience[1,2]. On a macroscopic
scale, it shows nonlinear fluctuations in pressure signals and
bed density. On a mesoscopic scale, it involves the forma-
tion, agglomeration, and fragmentation of bubbles. On a
microscopic scale, it involves the movement and collision
of medium particles. Therefore, understanding the correla-
tion mechanism of mesoscale structures during the fluidi-
zation process is a key challenge for enhancing fluidization
and separation processes, as shown in Figure 1.
RESEARCH PROGRESS
Bubble Behavior Identification
The study of individual bubbles in a fluidized bed of gas-
solid separation can be challenging. However, Zhang
Yadong et al. [4] proposed a scheme and algorithm to
identify bubbles in a dry separation fluidized bed. They
employed a high-speed dynamic camera to capture move-
ment images of bubbles in a two-dimensional fluidized
Figure 1. Schematic diagram of description between particles and unit equipment in mesoscale structure[3]
Additionally, numerical models have been created to
predict and simulate bubble behavior in the dry dense
medium fluidized separation process. These models con-
sider various factors such as fluid dynamics, particle interac-
tions, and bubble characteristics to provide insights into the
mesoscale behavior of bubbles. By utilizing these numerical
models, researchers can optimize the parameters and condi-
tions of the separation process to enhance its efficiency and
effectiveness.
Furthermore, the regulation of the mesoscale structure
in the gas-solid separation fluidized bed has been a subject
of detailed investigation. This involves the introduction of
external energy to control and manipulate bubble behav-
ior. The introduction of external energy, such as mechanical
vibration or acoustic waves, can significantly influence the
behavior of gas bubbles in the fluidized bed. This external
energy input can induce the formation of smaller bubbles,
enhance bubble coalescence, and promote the fracturing of
larger bubbles into smaller ones. By carefully controlling
these external energy inputs, researchers can manipulate the
bubble dynamics within the fluidized bed and optimize the
separation efficiency.
MESOSCALE STRUCTURE
The dense medium fluidized bed, which is a gas-solid two-
phase flow system, is commonly studied in the field of bub-
bling fluidization. It comprises an emulsion phase, formed
by particle aggregation, and a bubble phase, formed by gas
aggregation. The movement of bubbles leads to nonlinear
changes in key parameters such as apparent density and
pressure drop of the bed over time and space. These bubble
movements not only impact the even distribution of dense
medium particles but also influence the segregation behav-
ior of coal particles based on density. Thus, reducing the
disturbances caused by bubbles is crucial for improving the
quality of fluidization and enhancing the density segrega-
tion of coal particles. From a fluidization perspective, the
presence of bubbles defines the gas-solid separation fluid-
ized bed as a complex system, characterized by multiple
scales, nonlinearity, and transience[1,2]. On a macroscopic
scale, it shows nonlinear fluctuations in pressure signals and
bed density. On a mesoscopic scale, it involves the forma-
tion, agglomeration, and fragmentation of bubbles. On a
microscopic scale, it involves the movement and collision
of medium particles. Therefore, understanding the correla-
tion mechanism of mesoscale structures during the fluidi-
zation process is a key challenge for enhancing fluidization
and separation processes, as shown in Figure 1.
RESEARCH PROGRESS
Bubble Behavior Identification
The study of individual bubbles in a fluidized bed of gas-
solid separation can be challenging. However, Zhang
Yadong et al. [4] proposed a scheme and algorithm to
identify bubbles in a dry separation fluidized bed. They
employed a high-speed dynamic camera to capture move-
ment images of bubbles in a two-dimensional fluidized
Figure 1. Schematic diagram of description between particles and unit equipment in mesoscale structure[3]
