CN-122021217-A - UHT sterilization heat transfer simulation method and related device for granular liquid milk

CN122021217ACN 122021217 ACN122021217 ACN 122021217ACN-122021217-A

Abstract

The application discloses a UHT sterilization heat transfer simulation method and a related device for particle-containing liquid milk, and relates to the technical field of sterilization of dairy products, wherein the method comprises the following steps: based on UHT sterilization equipment parameters and process conditions, constructing a thermal resistance network model comprising a heat conduction and heat convection heat transfer path between the superheated water, the pipe wall, the cow milk and the particles; the method comprises the steps of calculating a fluid side convection heat transfer coefficient based on a thermal resistance network model and experience association, calculating an actual heat exchange amount according to actual change of temperature, taking single particles in particle-containing liquid milk as a research object, establishing a transient heat conduction partial differential equation describing change of the internal temperature of the particles along with time and a spherical coordinate system main equation reflecting physical change of the particles, determining simulation parameters and boundary conditions of a precooking and sterilizing stage, solving the transient heat conduction partial differential equation and the spherical coordinate system main equation, obtaining space-time distribution of a temperature field inside the particles, and realizing accurate simulation of the internal transient heat transfer process of particle phases in the rapid temperature field.

Inventors

DING TIAN
WANG XUHUI
ZHANG RUNRUN
HE JIAN
LIU DONGHONG
WANG XU
PEI XIAOYAN
ZHANG HONGYU
FENG JINSONG
QIAO HUAN

Assignees

浙江大学
内蒙古国家乳业技术创新中心有限责任公司
内蒙古伊利实业集团股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260130

Claims (10)

1. The UHT sterilization heat transfer simulation method for the particle-containing liquid milk is characterized by comprising the following steps of: based on UHT sterilization equipment parameters and process conditions, constructing a thermal resistance network model comprising a heat conduction and heat convection heat transfer path between the superheated water, the pipe wall, the cow milk and the particles; Calculating a fluid side convection heat transfer coefficient based on the thermal resistance network model and experience correlation, and calculating an actual heat exchange amount according to actual change of temperature; Taking single particles in the particle-containing liquid milk as a research object, and establishing a transient heat conduction partial differential equation describing the change of the internal temperature of the particles along with time and a spherical coordinate system main equation under a spherical coordinate system reflecting the physical change of the particles; and determining simulation parameters and boundary conditions of the precooking and sterilizing stages, and numerically solving a transient heat conduction partial differential equation and a spherical coordinate system main equation to obtain the space-time distribution of the temperature field inside the particles.
2. The UHT sterilization heat transfer simulation method of particle-containing liquid milk of claim 1, wherein the UHT sterilization heat transfer simulation method of particle-containing liquid milk further comprises calculating cumulative sterilization intensity inside the particles based on the spatial-temporal distribution of the temperature field inside the particles.
3. The UHT sterilization heat transfer simulation method of granular liquid milk according to claim 1, wherein the thermal resistance network model is represented as follows: ; ; Wherein, the The heat resistance of heat transfer of the tube type heat exchanger adopted for UHT sterilization is divided into three sections, namely superheated water heat convection, tube wall internal heat conduction and cow milk heat convection; B is the heat transfer distance; t is the temperature of the high-temperature fluid, and T is the temperature of the low-temperature fluid; 、 Convective heat transfer coefficients of the high temperature fluid and the low temperature fluid respectively; 、 Heat transfer areas of the high-temperature fluid and the low-temperature fluid respectively; is the logarithmic average area on both sides of the solid wall.
4. The UHT sterilization heat transfer simulation method for the particle-containing liquid milk of claim 1, wherein the numerical solution of the transient heat conduction partial differential equation and the spherical coordinate system main equation comprises the steps of utilizing COMSOL Multiphysics multiple physical field simulation software to numerically solve the transient heat conduction partial differential equation and the spherical coordinate system main equation.
5. The UHT sterilization heat transfer simulation method of granular liquid milk according to claim 1, wherein transient heat transfer partial differential equations are expressed as follows: ; Wherein, the 、、、、、、、 Respectively representing a mass coefficient, a damping mass coefficient, a diffusion coefficient, a convection heat transfer coefficient, an absorption coefficient, a conservation flux source, a heat conduction coefficient and a heat source; heat transfer is provided inside the particles.
6. The UHT sterilization heat transfer simulation method of granular liquid milk according to claim 5, wherein the spherical coordinate system principal equation is expressed as follows: ; Wherein, the Is the density of the particles; is specific heat capacity; Is the temperature; Representing time; is heat conduction; Is granule heat.
7. The UHT sterilization and heat transfer simulation method of liquid milk containing particles according to claim 6, wherein the method is characterized by numerically solving the transient heat conduction partial differential equation and the spherical coordinate system main equation to obtain the space-time distribution of the temperature field inside the particles, and specifically comprises: simplifying the transient heat conduction partial differential equation to obtain a simplified transient diffusion heat equation; Determining simulation input parameters of particles according to the simplified transient diffusion heat equation and the spherical coordinate system main equation, wherein the simulation input parameters comprise a mass coefficient, a damping mass coefficient, a heat source, a diffusion coefficient, a convection heat transfer coefficient, an absorption coefficient and a conservation flux source; And carrying out UHT sterilization heat transfer simulation of the liquid milk containing the particles according to simulation input parameters of the particles by utilizing multi-physical-field simulation software to obtain the space-time distribution of the temperature field inside the particles.
8. Computer device comprising a memory, a processor and a computer program stored on the memory and capable of running on the processor, characterized in that the processor executes the computer program to implement the UHT sterilization heat transfer simulation method of a liquid milk containing particles according to any one of claims 1-7.
9. A computer readable storage medium having stored thereon a computer program, characterized in that the computer program, when executed by a processor, implements the UHT sterilization heat transfer simulation method of a liquid milk containing particles according to any one of claims 1-7.
10. A computer program product comprising a computer program, characterized in that the computer program, when being executed by a processor, implements the UHT sterilization heat transfer simulation method of a liquid milk containing particles according to any one of claims 1-7.

Description

UHT sterilization heat transfer simulation method and related device for granular liquid milk Technical Field The application relates to the technical field of sterilization of dairy products, in particular to a UHT sterilization heat transfer simulation method and a related device for particle-containing liquid milk. Background Ultra high temperature transient sterilization (UHT) processes are the central means of ensuring commercial sterility of liquid foods. Currently, UHT process simulation technology for homogeneous fluids (such as pure milk) is mature, and the model is mainly based on the integral heat resistance theory of a heat exchanger and focuses on the temperature change prediction of a fluid phase. However, there is an increasing market demand for dairy products containing additives (if granules, cereal grains). The heat transfer mechanism of the multiphase system (continuous liquid phase-dispersed solid phase) in the UHT process is extremely complex, the prior simulation technology cannot be used for evaluating the actual sterilization effect (possibly causing microorganism residues) and texture change (such as particle clamping or excessive gelatinization) of the particle-containing product, and the process design has dead zones. Therefore, the development of the method capable of accurately simulating the internal transient heat transfer process of the particle phase in the rapid temperature change field has great significance for safe production, quality regulation and process optimization of the dairy product containing particles. Disclosure of Invention The application aims to provide a UHT sterilization heat transfer simulation method and a UHT sterilization heat transfer simulation device for liquid milk containing particles, which can accurately simulate the internal transient heat transfer process of a particle phase in a rapid temperature change field. In order to achieve the above object, the present application provides the following. In a first aspect, the application provides a UHT sterilization heat transfer simulation method for granular liquid milk, which comprises the following steps: based on UHT sterilization equipment parameters and process conditions, constructing a thermal resistance network model comprising a heat conduction and heat convection heat transfer path between the superheated water, the pipe wall, the cow milk and the particles; Calculating a fluid side convection heat transfer coefficient based on the thermal resistance network model and experience correlation, and calculating an actual heat exchange amount according to actual change of temperature; Taking single particles in the particle-containing liquid milk as a research object, and establishing a transient heat conduction partial differential equation describing the change of the internal temperature of the particles along with time and a spherical coordinate system main equation under a spherical coordinate system reflecting the physical change of the particles; and determining simulation parameters and boundary conditions of the precooking and sterilizing stages, and numerically solving a transient heat conduction partial differential equation and a spherical coordinate system main equation to obtain the space-time distribution of the temperature field inside the particles. In a second aspect, the application provides a computer device comprising a memory, a processor and a computer program stored on the memory and capable of running on the processor, the processor executing the computer program to carry out the steps of the UHT sterilization heat transfer simulation method for granular liquid milk. In a third aspect, the present application provides a computer readable storage medium having stored thereon a computer program which, when executed by a processor, performs the steps of the UHT sterilization heat transfer simulation method described above for granular liquid milk. In a fourth aspect, the present application provides a computer program product comprising a computer program which, when executed by a processor, implements the steps of the UHT sterilization heat transfer simulation method for granular liquid milk described above. According to the specific embodiment provided by the application, the application has the following technical effects: The application provides a UHT sterilization heat transfer simulation method and a related device for particle-containing liquid milk, which are used for constructing a thermal resistance network model comprising heat conduction and heat convection heat transfer paths among the four parts of superheated water, tube walls, cow milk and particles based on UHT sterilization equipment parameters and process conditions, calculating a fluid side convection heat transfer coefficient based on the thermal resistance network model and experience correlation, calculating actual heat exchange quantity according to actual change of temperature, taking single part