Study on Performance of High Low Temperature Radiator Group by a Combination Method-Reference-Cited by-同舟云学术

Study on Performance of High Low Temperature Radiator Group by a Combination Method

Published:2011-10 Issue: Volume:354-355 Page:394-400
ISSN:1662-8985
Container-title:Advanced Materials Research
language:
Short-container-title:AMR

Author:

Liu Shui Chang¹,Gu Zheng Qi²,Zhang Yong²,Fan Zun Jin²

Affiliation:

1. South China University of Technology

2. Hunan University of technology

Abstract

Establishes 3d numerical simulation model of water side and air side for ribbon-tubular radiator, studies effect of air velocity on air side heat transfer capacity and drag characteristics by using CFD method, based on double side 3d simulation result, and then calculates the import and export water temperature of the high low temperature radiator group with procedure. The calculated water temperatures are coinciding with experimental data. Then analyzes the influence rule of different wave combinations to the radiator group performance by the method of simulation and procedure calculation, the result is reference theory for the structure optimization and matching of the radiator group.

Publisher

Trans Tech Publications, Ltd.

Subject

General Engineering

Link

https://www.scientific.net/AMR.354-355.394.pdf

Reference126 articles.

1. 1Physical model The ribbon-tubular radiator group studied in this paper includes high temperature radiator (radiator in engine cooling system) and low temperature radiator (inter cooler) ; its core body are composed by the same size flat tubes and ripple thermal tape, thermal fluid flows in the flat tubes, cooling air cross ripple thermal tape and flat tube outside, as shown in figure 1. The core body in low temperature radiator constitutes by two rows of water pipes, and the high temperature radiator has three rows, the coming air cross the low temperature radiator first. Fig. 2 Air side CAD unit model Air flow Water flow Water pool Core body Air flow pipe tape Wave distance Fig. 1 Structure of ribbon-tubular radiator Fig. 3 Water side CAD model The core body of the radiator is always made up of the dozens or even hundreds of pipes and thermal tape, the wall of the pipes and thermal tape are very thin; executing CFD simulation of whole radiator will cause a huge number of grid units, performance of the current computer is hard to meet the computing needs. According to the structure characteristics of the ribbon-tubular radiator, take one layer radiator unit for air side model, the unit is formed by one wave distance tape and related pipes, and the unit entrance and exit throughout the core body of the radiator, the model of the low temperature radiator is shown in figure 2; the water side model is a water pipe, it connects the ends of the radiator inlet and outlet pool, shown in Figure 3.

2. 2 The mathematical model The velocity of double side is relatively low, density can be approximately constant, the flow field is 3 d incompressible flow one. The core body of the radiator is composed by dense arrays of flat tube and wave tapes, the flow field is easy to separate, and can be taken as turbulent. In the calculation, basic control equations [9] are following: (1) Continuous equation ; （1） (2) Momentum equations , （2） ; （3） (3) Energy equation . （4） The is the average speed in the formula above, and the, respectively is the average velocity component of x, y, z direction, the T is temperature, the k is heat transfer coefficient of hydraulic oil, the Cp is the specific heat capacity of hydraulic oil, the ST is the hydraulic oil internal heat source and the heat from mechanical energy because of viscosity.

3. 3The simulation process After establishing of CAD model, the ICEM CFD software is adopted to generate meshes, about 2. 6 million of meshes on water side and about 1. 7 million on air side, then the grid file is imported to CFD calculation software FLUENT, uses the k-ε turbulent model to solve the results. Uses SIMPLE method for pressure-speed coupled. Boundary conditions are set as flowing: inlet velocity on the water side of the high and low temperature radiators are respectively 1. 54 m/s and 1. 24 m/s, all exports are pressured outlet, wall of pipes are constant temperature wall; In order to get wind resistance characteristic curve of the radiator group, the entrance of the air side are set a series of speeds(2 m/s, 6 m/s, 10 m/s, 14 m/s), the entry air temperature during experiment test is 18. 5℃, wall of pipes and wave tapes are constant temperature wall, the entry conditions of high temperature radiator is the export conditions of low temperature radiator.

4. 4 The simulation results Fig. 4 Heat tranfer coefficient curves Fig. 5 Air side resistance curves The heat transfer coefficient abstained from simulation of the high and low temperature radiators water side are respectively 1302. 5 (W/ m2 * K) and 1140. 5 (W/ m2 * K). Read the heat transfer coefficient and pressure loss on the air side, convert air velocity into the air flow, using data processing software to get the curves of heat transfer coefficient and air resistance characteristic of high and low temperature radiator as shown in figure 4 and figure 5. From the figure 4 and figure 5, it can be seen that when air velocity and flow rate increase, heat transfer coefficient of radiator on air side enhances with the air resistance increasing; At the same time, because speed has been declined by the resistance during through the low temperature radiator, heat transfer coefficient and pressure drop of low temperature radiator are is higher than the high temperature radiator, and this trend increases as speed increases. Fig. 6 Matching of fan working point Fan curve Radiator group curve.

5. 5 Fan working point Processing the resistance loss data of the high and low temperature radiator gained from the above simulation, get system resistance characteristic curve of radiator group, as shown in figure 6, find the intersection of this curve and fan characteristic curve, it is working point, as shown in figure 6, the air flow is 59. 12 m3/s. 2 Water temperature of Import and export.