Factors Affecting Heat Transfer Coefficient Of Plate Heat Exchanger
Compared with other equipment, plate heat exchanger has high heat exchange efficiency, convenient cleaning and simple maintenance. It is one of the main equipment of heat exchange station in central heating project. Since this is the case, we need to discuss three main factors that affect the Heat transfer coefficient of equipment to achieve better heat supply quality:
1. Pressure drop control of plate heat exchangers
The pressure loss of equipment is an important point to consider. Based on past work experience, the pressure loss of the primary network in larger centralized heating projects is generally around 100kPa, which is relatively economical and reasonable. Under these conditions, the heat exchange area obtained can not only meet the requirements of the working conditions, but also save investment. According to the above conditions, we set the pressure loss of the equipment at around 50kPa. If this value is set at 30kPa, the corresponding heat exchange area will increase by about 15% -20%, which will result in an increase in initial investment and maintenance costs. However, in some projects where the working pressure of the primary network is low and the pressure drop is required to be small, there are also cases where the latter is chosen.
2. Working parameters
The influence of operating parameters on heat transfer coefficient is obvious.
Among them: p-heat exchange capacity;
K - heat transfer coefficient;
F - Heat exchange area;
tm - Logarithmic mean temperature difference.
We can design and verify plate heat exchangers, and the working parameters will affect the determination of heat transfer coefficient and heat transfer area. In the field of air conditioning, we often obtain a larger heat transfer area when selecting equipment, which is because the Δ tm of the air conditioning unit during heat exchange is smaller.
3. Plate embossing
The original plates of the equipment are pressed with regular ripple patterns, which can enhance the disturbance of the fluid in the flow channel and achieve the purpose of enhancing heat transfer. Due to different design ideas and process conditions, various manufacturers produce different types of corrugated plates. Taking the herringbone pattern as an example, the angle of the herringbone pattern determines pressure loss and heat transfer efficiency, while the obtuse angle herringbone pattern provides high resistance and large heat transfer power. Sharp angle herringbone pattern provides low resistance and small heat transfer power. When designing products, it is possible to optimize the processing based on the characteristics of each application. If the flow rates of one side and two sides of the circulation are different, the equipment can configure each corrugated plate in a specific proportion to achieve great heat transfer efficiency and better energy conservation.
The article introduces three main factors that affect the Heat transfer coefficient in detail, and I believe you will have a new understanding after reading it. From the perspective of losses in each link, it is necessary to consider both operability and economy, and combine the above factors to improve and optimize the product, in order to achieve better heating efficiency.
