Plate heat exchanger flow pattern
The flow pattern of the plate heat exchanger has countercurrent, downstream and mixed flow patterns. Under the same working conditions, the logarithmic mean temperature difference is the largest in the counterflow and the smallest in the downstream flow, and the mixed flow pattern is between the two.
The method for increasing the logarithmic mean temperature difference of the plate heat exchanger is to adopt a mixed flow pattern of countercurrent or near countercurrent as much as possible, to increase the temperature of the hot side fluid as much as possible, and to reduce the temperature of the cold side fluid. For a single-flow plate heat exchanger, For the convenience maintenance, the fluid inlet and outlet pipes should be arranged on the side of the fixed end plate of the heat exchanger. The greater temperature difference of the medium, the stronger natural convection of the fluid, and the more obvious influence of the formed retaining zone. According to the hot fluid up and down, the cold fluid is placed in the upper and down arrangement to reduce the influence of the retention zone and improve the heat transfer efficiency.