Development and application of numerical model of thermal sensors for thermal protective clothing evaluation based on CFD simulation

PurposeThe purpose of this paper is to study the heat transfer effect of copper sensor and skin simulant on skin.Design/methodology/approachFor the sensor, the physical and mathematical models of the thermal sensors were used to obtain the definite conditions in the heat transfer process of the sensor, and the heat transfer models of the two sensors were developed and solved respectively by using ANSYS WORKBENCH 19.0 software. The simulation results were compared with the experimental test results. For the skin, the numerical model of the skin model was developed and calculated. Finally, the heat transfer simulation performance of the two sensors was analyzed.FindingsIt is concluded that the copper sensor is more stable than the skin simulant, but the material and structure of the skin simulant is more suitable for skin simulation. The skin simulant better simulates the skin heat transfer. For all the factors in the model, the thermal properties of the material and the heat flux level are the key factors. The convective heat transfer coefficient, radiation heat transfer rate and the initial temperature have little influence on the results, which can be ignored.Research limitations/implicationsThe results show that there are still some differences between the experimental and numerical simulation values of the skin simulant. In the future, the thermal parameters of skin simulant and the influence of the thermocouple adhesion should be further examined during the calibration process.Practical implicationsThe results suggest that the skin simulant needs to be further calibrated, especially for the thermal properties. The copper sensor on the flame manikin can be replaced by the skin simulant with higher accuracy, which will be helpful to improve the accuracy of performance evaluation of thermal protective clothing.Social implicationsThe application of computational fluid dynamics (CFD) technology can help to analyze the heat transfer simulation mechanism of thermal sensor, explore the influence of thermal performance of thermal sensor on skin simulation, provide basis for the development of thermal sensor and improve the application system of thermal sensor. Based on the current research status, this paper studies the internal heat transfer of the sensor through the numerical modeling of the copper sensor and skin simulant, so as to analyze the effect of the sensor simulating skin and the reasons for the difference.Originality/valueIn this paper, the sensor itself is numerically modeled and the heat transfer inside the sensor is studied.

CHARACTERISTICS OF HEAT TRANSFER DURING COOLING DOWN PROCESS IN A SINGLE CARGO TANK OF LNG CARRIER

A deep understanding of heat transfer characteristics is essential in evaluating risk and putting forward any option for the Liquefied Natural Gas (LNG) tank cooling down process. A novel Computational Fluid Dynamics (CFD) model was built to perform the flow and heat transfer simulation of the process. The predicted results agreed well with the test data from a prototype LNG tank. Then the heat transfer characteristics of the process were analysed. It was found that the vapour temperature and density were linearly varying and became stable after 2.3 hours. A sudden pressure drop risk was identified during the process, which will cause the inwards collapse risk of the invar membrane. Then the proposals to prevent the risks of the inwards collapsing membrane are presented. The heat transfer characteristics of the vapour and different membrane layers were analysed in detail, and if the suggested option was to be implemented this could save about 39% of LNG consumed.

3D Heat transfer Simulation of an injection mold: comparison between ANSYS Workbench and ANSYS Mechanical APDL

Because of recent advancements in additive manufacturing, fabricating conformal cooling channels (CCCs) has become easier and more economical. In the injection molding process, CCCs provide higher cooling performance than standard (straight drilled) channels. The major reason for this is that CCCs may follow the courses of the molded geometry, whereas typical channels created using traditional machining processes cannot. Using CCCs can reduce thermal strains and warpage while also improving cycle time and achieving a more uniform temperature distribution. CCC, on the other hand, has a more complicated design procedure than traditional channels. Simulations using computer-aided engineering (CAE) are critical for achieving an effective and cost-effective design. This article compares two ANSYS modules for the purpose of validating results. It can be inferred that the two modules produce similar results for models with fine mesh. As a result, the ANSYS module to work on should be chosen depending on the job's goal as well as the CAD geometry's complexity.