How to achieve small temperature difference heat transfer in spiral plate heat exchangers
Spiral plate heat exchangers enhance heat transfer through structural optimization, improve turbulence level through channel design, reduce heat transfer thermal resistance, and achieve efficient heat transfer with small temperature differences (usually below 5 ℃). The core logic is the heat transfer coefficient and heat transfer area. The specific implementation method is as follows:
Spiral plate heat exchangers enhance heat transfer through structural optimization, improve turbulence level through channel design, reduce heat transfer thermal resistance, and achieve efficient heat transfer with small temperature differences (usually below 5 ℃). The core logic is the heat transfer coefficient and heat transfer area. The specific implementation method is as follows:
1. Spiral flow channel enhances turbulence and reduces heat transfer resistance
Cold and hot media flow in a spiral flow channel, with a narrow cross-section and long length. When the fluid flows, it is prone to strong turbulence (with a high Reynolds number Re), breaking the heat transfer boundary layer and reducing the thermal resistance caused by laminar flow.
Spiral flow channels have no dead zones, uniform medium flow velocity and long path, and more complete contact with the heat exchange plate surface, avoiding low local heat transfer efficiency and achieving efficient heat transfer even under small temperature differences.
2. Large specific surface area+tight fit, improving heat transfer capacity
The spiral structure formed by rolling two metal plates has a much larger heat transfer area per unit volume than a shell and tube heat exchanger. Under the same equipment volume, it can provide more heat transfer contact surfaces and compensate for the insufficient heat transfer driving force caused by small temperature differences.
The heat exchange plates are tightly adhered, with a small spacing between plates (usually 2-10mm), and the flow paths of the cold and hot media are close, resulting in a short heat transfer path, reducing heat loss, and improving heat transfer efficiency under small temperature differences.
3. Reverse flow arrangement+structural sealing to enhance heat transfer and temperature difference
The cold and hot media flow in a counterflow manner (with the flow direction of high-temperature and low-temperature media being opposite), which can maintain a logarithmic average temperature difference. Even if the overall temperature difference is small, the medium can maintain a stable heat transfer driving force throughout the entire flow channel.
The spiral structure has good sealing performance, avoiding medium leakage or short circuit, ensuring sufficient heat exchange between cold and hot media, and preventing further reduction of heat transfer temperature difference due to medium mixing, ensuring heat transfer effect under small temperature difference conditions.
4. Material and channel optimization, suitable for small temperature difference scenarios
Heat exchange plates are often made of materials with high thermal conductivity, such as carbon steel and stainless steel, to reduce the thermal resistance of the plates themselves and accelerate heat transfer.
By adjusting the thickness of the spiral plate and the width of the flow channel, different medium viscosities and flow rates can be adapted to ensure that a reasonable flow rate can be maintained under small temperature differences, avoiding a decrease in heat transfer coefficient caused by low flow rate.