Design Research Of The Thin Film Evaporator Equiped With Dimple Jacket

Thin-film evaporators are kinds of evaporation equipment, which features high efficiency and energy saving, widely used in the field of fine chemicals, pharmaceuticals and foodstuff industry. The short pipe type dimple jacket, which is ease of manufacturing, applied to the thin film evaporator can increase stability of the evaporator, reduce the thickness of the barrel and therefore improve the heat transfer performance. The performance study of short tube dimple jacket has a very important value in engineering.In this paper, major research work and main results are summarized as follows:(1) The existing various design calculation methods of dimple jacket were compared. A set of evaporation area of2.5m20gap type scraper film evaporator was designed.(2) The complete model of the dimple jacket and the barrel surrounded by it was established. The finite element method was used to analyze the structure strength and stability of the dimple jacket, the structural stability of the design was verified.(3) The one-eighth model of short tube type dimple jacket and the barrel was established, using ANSYS software to simulate the temperature distribution of the structure, The simulation results show that the overall temperature distribution is relatively uniform, there is a large temperature gradient at the position where short tube is connected with the jacket.(4) Stress assessment of thin film evaporator was carried out through thermal plus mechanical load analysis and strength analysis; the assessment results show that the local primary membrane stress, the general primary membrane stress and primary plus secondary stress are all relatively small. The structure is safe and reliable, fully able to adapt to different working conditions.(5) The structural stress on the thin film evaporator with different diameters was studied by means of parametric modeling. The results showed that the wall thickness of the jacket and the barrel does not need to be increased with the increase of the barrel diameter. Finite element calculation of wall thickness value is less than calculated value of the formula of dimple jacket, strengthening of short tube is not fully considered in the formula. Taking into account strength and stability, the dimple jacket applied to thin-film evaporator allows large thin-film evaporator to use the same wall thickness as small-size thin-film evaporator, to avoid the malpractice of the sharp increasing in wall thickness along with barrel diameter increasing of external pressure vessel. The mainly stress state of dimple-jacket thin film evaporator with large diameter and Multi-number tube is bending stress.