Abstract:

The heat transfer and resistance characteristics of the detachable plate heat exchanger composed of two different corrugated depth plates were studied by experimental method and comparative method. Each kinds of corrugated depth plates were divided into three corrugated angle combination of the hard plate (63°/63°), or soft plate (29°/29°), or mixed plate (63°/29°). The test was divided into two working conditions, one was that flow velocity of hot side synchronize with cold side, both sides were equal in every moment; The other was that flow velocity of hot side was always 0.5 m/s, flow rate of cold side was increased from 0.2 m/s to 0.9 m/s. The medium of each side was water. The value of the total heat transfer coefficient and pressure drop of two conditions were calculated, and the corresponding curves were described. The experiment proved that the total heat transfer coefficient of the shallow density corrugated plate was higher than that of the ordinary corrugated plate at the same corrugated angle combination, the average value was higher than 140 W/(m²·K), so the heat transfer coefficient was increased by 1.9% on average, and the difference of the heat transfer coefficients in the mixed plates was above 300 W/(m²·K), which was up to 4.8%, and the change trend of flow resistance was the same as the heat transfer coefficient. The functions of Nusselt number and friction factor were obtained, the correctness of the experiment was proved by comparing with the existed research results, it also revealed that there was room for optimization of the heat transfer performance and resistance of the two kinds of corrugated plates, which pointed out the direction for further research. The experiment also shown that the difference of the functions of Nusselt and friction coefficient about two kinds of corrugated plates with the same geometry size except the depth and the same structure were obvious.

Key words: gasketed plate heat exchanger, corrugated plates, heat transfer, flow

摘要：

通过实验的方式和对比的方法对两种不同波纹深度板片组成的可拆板式换热器的传热及阻力特性进行研究，每种深度板片组成的板式换热器采用硬板63°/63°、软板29°/29°和混合板63°/29°三种波纹角度组合，此实验采用水/水换热，设置了两种工况，一种是冷热两侧等流速，另一种是固定热侧流速，计算两种工况下传热系数和压降的数值，描绘出对应的曲线。实验证明相同波纹夹角板片组合，该浅密波纹板片的传热系数均高于普通波纹板片，平均高于140 W/(m²·K)，即传热系数平均提高1.9%，在混合板中两者传热系数的差别在300 W/(m²·K)以上，提高达4.8%，阻力的变化趋势与传热系数相同。推导出每组设备适用于一定Reynolds数范围的Nusselt数方程和摩擦系数方程，与已有研究成果对比分析，证明了该实验的正确性，同时也揭示这两种波纹板片的传热和阻力性能有优化的余地，为进一步的研究指明了方向。该实验也表明，除深度外的几何尺寸和结构均相同的两种波纹板片，虽然外形接近，但对应的Nusselt数和摩擦系数关系式却不相同，而且差别很大。

关键词: 板式换热器, 波纹板片, 传热, 流动