Jinfeng Wang

Numerical Simulation on Temperature Distributions to Cold Store

On the basis of previous work, the simulation condition of cold store was improved to reduce calculation error. The SIMPLE algorithm and Boussineq assumption were used and the turbulent intensity was also set. The numerical simulation results reflected that the temperature distribution was closer to the previous experimental results after using new method. The error between simulation values and experimental values was decreased. The simulation result showed that temperature of corner was highest in the cold store. The temperature change of the cold store in the cooling process could be better predicted by using modified simulation method and the accuracy of numerical simulation of cold store in the cooling process could also be validated.

Cooling Process after HTST Orange Juice Sterilization Optimization Based on CFD

In order to study the juice cooling process after sterilization to obtain the accurate process and reduce the energy used in the cooling, the orange juice in can high temperature short time (HTST) sterilization process was calculated. The maximum temperature of juice in can was defined as 60°C. By using FLUENT, a kind of software which combines hydrodynamics, mathematics and computer technology, we were able to put different fluids into analog computation and numerical experiment to solve problems related to hydrodynamics. Orange juice cooling numerical experiment after HTST sterilization was carried out. The optimization cooling process was obtained: 20°C(293K),14 minutes;15°C(288K),13 minutes; 10°C(283K) ,13minutes; 5°C(278K), 12minutes and 0°C(273K), 12minutes. Using Carnot efficiency in Reverse Carnot cycle, the energy consumption was: 288W, 325W, 348W, 391W, 417W in accordance. And in the result, the optimized process was : 20°C(293K),12 minutes.

Application of Computational Fluid Dynamics (CFD) Used in Simulation of Flow Distribution for Air Condition

In this article, the application of Computational Fluid Dynamics (CFD) technology in the field of Heating Ventilation & Air Condition was introduced, and the research progress in optimizing the simulation of air-conditioned room was summarized. Some domestic and foreign studies on air conditioning operation and energy saving were illustrated about the effects of different installation locations, blow angles and air supply modes, which would provide a theoretical basis and scientific guidance for air-conditioning systems to optimize the design. Based on previous results, the development of further research on CFD in the simulation of air-conditioning in future was analyzed.

Theoretical Study of Temperature Distribution though Pasteurization for Orange Juice Based on 3D CFD Simulation

Computational fluid dynamics is a blanch of hydromechanics which is used to analyze the properties and heat transfer for different flows. With the developments of the computer science and CFD software itself, CFD has been applied into every field in engineering which can save the cost and time of research. This article simulated three different temperatures (85°C, 88°C, 90°C) of pasteurization to orange juice and got the temperature field in each pasteurization temperature After compared with the experimental data, the simulation model was improved and optimal computational way was got finally.

Theoretical Study and 3D CFD Simulation of Temperature Distribution through HTST for Orange Juice

Heat sterilization has a long history. However, due to lacking of precise research, the sterilization relies mainly on experience, which leads to uncompleted sterilization or energy wastage. Computational fluid dynamics (CFD) is a tool to study the flow and heat transfer properties of different kinds of fluid. With the development of computer science and the improvement of CFD itself, CFD has been widely used in the industrial engineering. In this work, the CFD is used to study variation of the central temperature of an orange juice model under the HTST sterilization. Compared with the experiment results, the current simulation method is optimized and the error is reduced.

Numerical Simulation on Comparison of Air Flow Distribution with Different Algorithms

To get the air distribution in a small cold store, a mini type cold store ( 4. 5 m ( l)×3. 3 m (w )×2. 5 m (h) ) was referenced. The model of the small cold store was established in the software named GAMBIT and after this the three-dimensional numerical simulation was used. The different simulation result was verified by the experiments. The accuracy of simulation in airflow field in cold stores was studied by comparison of various mesh rezoning, various decoupling methods for airflow speed and pressure. The results showed that 10cm dimensional accuracy was the suitable mesh size for the calculation speed without affecting the simulation accuracy, and the SIMPLE algorithm was better for the PISQ algorithms to simulate steady air flow of the cooling process in a cold store without products. It was concluded that there was a large circumfluence in the flow field, the speeds in the center and corner were lower than those in other places. The distribution of flow speed in the horizontal plane had a good symmetrical, however that in the vertical plane was lower than that in the center, but higher upwards and downwards. The study validated 3D CFD simulation technology for the small cold store. The results of the research offered the optimized methods of using CFD and acted as the reference of the simulation model in the cold store.

Computational Fluid Dynamics Simulation about the Impact of Products on a Cold Store

The unreasonable airflow distribution often occurs in the cold store. Some specific parameters of airflow in the cold store are difficult to obtain in the practical experiments. The unreasonable airflow causes quality decline and large energy consumption. In this paper, the airflow distributions in an empty commercial cold store and the cold store filled with products were studied by CFD and investigated using the 3D modeling method which combined SIMPLE calculation method and finite-volume method. Meshes of the fan were refined locally with the airflow near the walls was modified by applying the non-wall function. Through comparing the airflow distributions in the empty cold store and in the cold store filled with products, differences such as the lower margin velocity, the smaller width and the deviation of the main steam in the cold store filled with products were found.

Theoretical Study and CFD Simulation of Airflow Distribution through a Cold Store

Recently, the quantity of the cold store has been increased quickly. It is a key point to improve the uniformity of airflow field to the cold store. In this paper, a model of simulating cold store by computational fluid dynamics (CFD) was introduced. Simple algorithm combined with Boussineq assumption was used and turbulent equation combined with standard wall function was applied to define the flow of air in the cold store. Both the structured mesh and unstructured mesh to cold store model were simulated. The simulation methods of airflow in a cold store between three-dimension (3D) technology and two-dimension (2D) technology were also discussed. The experiment was validated and proved that unstructured grid was in better agreement with the result of experiments and it was gotten that the three-dimension (3D) technology had a higher accuracy in simulation of airflow distribution. The airflow distribution in the vertical plane and horizontal plane in cold store were gotten, respectively.

Simulation Based on CFD to Temperature and Flow Fields of Vertical Air Conditioner Operation

The sales volume of vertical air conditioner in China mainland has developed rapidly. The researches in the field to the operation of vertical air conditioner are lacked since it is hardly to analyze different kinds of operating condition. Computational Fluid Dynamics (CFD) has been applied in engineering with the advance of the computer science and technology. In this article, both temperature and air flow distributions were analyzed to a meeting room which putted a vertical air conditioner. The model was used and the equations for numerical simulation (e.g. energy, residual, continuity, etc) were chosen as second order to get the higher accuracy. The results to simulation were showed reasonable and could offer a reference to the practical.

Computational Fluid Dynamics Simulation about Comparison of Different Forms of Return Air in a Small Cold Store

The quantity of the cold store in our country has been rapidly rising since the 1990s, however, the flow field in the cold store is difficult to obtain accurately by experiments. With reference to the experiences in previous numerical simulations in this paper, CFD is used for analyzing two forms of return air in the cold store with the Finite Volume Methods and the SIMPLE Revised. As a result, Combining with the non-equilibrium wall function, it is found that taking the way of return air on both sides of the fan is more reasonable and the cooling consumption of the empty cold store can be saved before the products enter the cold store. Furthermore, the numerical simulation results can provide reference for choosing fans in the small cold store.