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CN-121980741-A - Passive cold storage tank design method based on multi-physical field coupling simulation and passive cold storage tank

CN121980741ACN 121980741 ACN121980741 ACN 121980741ACN-121980741-A

Abstract

The invention provides a passive cold storage box design method based on multi-physical field coupling simulation, which comprises the following steps of 1, establishing a three-dimensional geometric model of a passive cold storage box in COMSOL Multiphysics, wherein the three-dimensional geometric model comprises a box body heat preservation layer, an internal cavity and an ice plate, and endowing the ice plate with a phase change material attribute module, 2, setting multi-physical field boundary conditions and initial states, and setting a transient solver, 3, setting a solid heat transfer control equation, and 4, obtaining a simulated temperature-time curve through transient solving by adopting parameterized scanning, and screening ice plate distribution meeting the cold storage condition. The method can obtain the temperature field distribution and the temperature-time change curve in the passive cold storage box, thereby determining a preferred arrangement mode meeting the cold storage requirement, and the temperature of the cavity in the cold storage box can be maintained to be less than or equal to 15 ℃ by adopting the mode, and the duration time is more than 40 hours.

Inventors

  • FENG YI
  • WU BO
  • LIANG LINZHI
  • QU XIONGWEI
  • ZHENG DE

Assignees

  • 广东炜林纳新材料科技股份有限公司

Dates

Publication Date
20260505
Application Date
20251208

Claims (10)

  1. 1. A passive cold storage box design method based on multi-physical field coupling simulation is characterized by comprising the following steps: step 1, a three-dimensional geometric model of a passive cold storage box is built in COMSOL Multiphysics, wherein the model comprises a box body heat preservation layer, an internal cavity and an ice plate, and a phase change material attribute module is endowed to the ice plate; Step 2, setting a boundary condition and an initial state of multiple physical fields, and setting a transient solver; step 3, setting a solid heat transfer control equation; And 4, obtaining a simulated temperature-time curve through transient solving by adopting parameterized scanning, and screening the ice plate distribution meeting the cold storage condition.
  2. 2. The passive cold storage box design method according to claim 1, wherein the ice plates in the step 1 comprise a first ice plate, a second ice plate and a third ice plate which are sequentially arranged, the phase change temperatures of the first ice plate, the second ice plate and the third ice plate are independently set to-10 ℃, and the latent heat of phase change is independently set to 170-230J/g.
  3. 3. The method for designing a passive cold box according to claim 1, wherein the boundary condition of the multiple physical fields in the step 2 is that the set environmental temperature is 20+/-5 ℃; And/or the initial state in the step 2 is that the temperature of the ice plate is set to be-20 ℃ and the air temperature of the inner cavity is set to be-20 ℃; And/or setting the time range of the transient solver in the step 2 to be 0-96 h, and adopting self-adaptive adjustment for the time step.
  4. 4. The passive cold box design method according to claim 1, wherein the control equation in the step 3 is a heat conduction equation and a heat convection equation; The heat conduction equation comprises a heat transfer control equation of the box body heat preservation layer: ; Wherein, the The density of the cold storage box is set to be 28-32 kg/m 3 ; The specific heat capacity of the cold storage box is 1800-2100J/kg.K; The heat conductivity coefficient of the cold storage box is set to be 0.028-0.034W/(m.K); and a storage heat transfer control equation: ; Wherein, the Is the density of the stock; specific heat capacity for the storage; is the thermal conductivity of the storage; the thermal convection equation comprises a thermal convection equation generated between the outer wall of the box body and the external environment: ; Wherein, the The heat exchange coefficient of natural convection of air is set to be 8-10W/(m 2 .K); setting the temperature as 293.15+/-5K for the external environment temperature; the heat conductivity of the cold storage tank is set to be 0.028-0.034W/(m.K).
  5. 5. The method for designing a passive cold storage tank according to claim 1, wherein the cold storage condition in the step 4 is that the temperature of the internal cavity is less than or equal to 15 ℃ and the duration is more than or equal to 40h.
  6. 6. The method of designing a passive cold box according to claim 2, wherein before the simulated temperature-time curve is obtained by transient solution in step 4, further comprising assigning differentiated PCM parameters to each of the ice plates; the phase transition temperature of the first ice plate is set to be 2-10 ℃ and the latent heat is set to be 200-230J/g; and/or the phase transition temperature of the second ice plate is set to be-2 ℃ and the latent heat is set to be 200-230J/g; and/or the phase transition temperature of the third ice plate is set to be 2-10 ℃ and the latent heat is set to be 200-230J/g.
  7. 7. The passive cold box design method of any one of claims 1-6, further comprising: Step 5.1, assembling a passive cold storage box according to the distribution of the ice plates in the step 4, and filling ternary composite phase change materials into the ice plates; Step 5.2, testing and obtaining actual measurement temperature-time curves of a plurality of temperature measuring points in the passive cold storage box in an environment of 20+/-5 ℃; And 5.3, comparing the actually measured temperature-time curve with the simulated temperature-time curve, and if the average deviation is more than 5%, iteratively adjusting the position of the ice plate or the proportion of the ternary composite phase change material, wherein the actually measured cold insulation time is more than or equal to 40 hours.
  8. 8. The passive cold box design method of claim 7, wherein the number of iterations in step 5.3 is less than or equal to 5.
  9. 9. A passive cold storage tank, characterized in that a plurality of ice plates are arranged inside, and the positions of the ice plates are obtained according to the passive cold storage tank design method of any one of claims 1-8.
  10. 10. The passive cold storage box of claim 9, wherein the ice slab is filled with a ternary composite phase change material consisting of an aqueous mannitol solution, an aqueous sodium formate solution, and a water-absorbing resin; Wherein the concentration of the mannitol aqueous solution is 0.8% -1.3%, the concentration of the sodium formate aqueous solution is 1% -5%, and the concentration of the water-absorbing resin is 0.3% -2%.

Description

Passive cold storage tank design method based on multi-physical field coupling simulation and passive cold storage tank Technical Field The invention belongs to the technical field of phase change materials, and particularly relates to a passive cold storage tank design method based on multi-physical field coupling simulation and a passive cold storage tank. Background The passive cold storage box is used as key equipment for cold chain transportation, and the cold insulation performance of the passive cold storage box directly influences the safety of sensitive materials such as biological agents, vaccines and the like. There are significant limitations to the current mainstream technology. Firstly, the aging defect is that the existing cold storage box generally depends on a single cold source (such as ice bags or dry ice), is limited by insufficient latent heat of phase change of cold storage materials and heat loss of a box body structure, the actually measured cold insulation time under the environment of 10 ℃ is generally less than 24 hours (CN 115218534B indicates that the traditional scheme is only 29.26 hours), and the rigidity requirement of the environment-crossing logistics and other scenes on the long-term effective temperature control is difficult to meet. Secondly, the material performance is bottleneck that the phase transition temperature of the Phase Change Material (PCM) is inversely related to latent heat (as disclosed in CN115218534B, a high-latent heat material is difficult to have low-temperature phase transition characteristics), and problems of supercooling, phase separation and leakage are easy to occur. The PCM phase transition temperature on the market is concentrated in a narrow temperature range, and is difficult to adapt to the wide range of temperature change in the transportation process. In addition, the design of the passive cold storage structure is still rough, the layout of the ice plate depends on the rule of experience, the cold bridge effect caused by the non-uniform temperature field in the box body (for example, the heat flow density at the sealing position of the box door can reach 3.2 times of the side wall) is not considered, the local cold leakage is aggravated, and meanwhile, the PCM parameters and the thermodynamic characteristics of the structure are decoupled, and a system optimization means is lacked. It is therefore highly desirable to break through the cold-keeping bottleneck through material-structure synergy innovations. COMSOL Multiphysics is used as a multi-physical field coupling simulation platform based on an advanced numerical method, and shows remarkable technical advantages in the field of temperature field simulation. The core capability of the method is that a plurality of physical fields are cooperatively solved (such as coupling of fluid dynamics and heat transfer) and high-precision transient analysis is carried out, so that a scientific tool is provided for thermodynamic optimization of cold chain equipment. Through transient modeling of latent heat release/absorption of the phase change material, three-dimensional geometric modeling of the ice plate and definition of material thermophysical parameters (such as heat conductivity coefficient and specific heat capacity) and boundary conditions (such as ambient temperature and heat flux), the software can accurately simulate non-uniform temperature field distribution, so that in the design of the passive cold storage box, the experimental design is driven based on the multi-physical field coupling simulation result, the development of the passive cold storage box can be changed from experience leading to data driving, the experimental period is effectively shortened, and the research and development efficiency is improved. Disclosure of Invention The present invention aims to solve at least one of the technical problems in the prior art described above. Therefore, the invention provides a design method of a passive cold storage tank based on multi-physical field coupling simulation and the passive cold storage tank. According to the method, first, COMSOL Multiphysics software is utilized to simulate the positions of ice plates of the existing passive cold storage box and materials with different phase transition temperatures, distribution of temperature fields in the passive cold storage box and temperature change curves with time under different arrangement modes and ice plate intervals are obtained, an optimal arrangement mode meeting the cold storage requirement is screened, next, mannitol and sodium formate phase transition materials with different concentrations are synthesized according to simulation results, the passive cold storage box is assembled, the simulation results are verified through comparison of the actually measured temperature curves and the simulation results, and finally, the material-structure coupling design closed loop is achieved. According to a first aspect of the