Baffled rod heat exchanger design

The baffle rod heat exchanger is also designed in accordance with the GB151 standard, except that the baffle plate becomes a baffle rod. For the layout of the baffle rod, please refer to the relevant introduction. Take a look at the atlas. There is an example of a baffle rod heat exchanger in it. Haha, if you haven’t painted this before, you might think it’s mysterious. If you draw one side carefully, you will know that it is very simple. Just use a ring, weld a thin rod to it, and then thread the pipe through it. The baffled rod heat exchanger is a new type of heat exchanger with high heat transfer efficiency, good pressure drop and anti-vibration effect. The baffles of traditional shell-and-tube heat exchangers generally come in two forms, namely single arcuate and double arcuate (including annular). The medium flow conditions are shown in Figure 1. Main flow area A is the main heat transfer area, and about 85% of the heat transfer is completed in this area. The fluid sweeps across the tube bundle, exhibiting cross-section heat transfer, and can reach a turbulent flow state when Re is low. Zone B is the downstream zone, which can complete about 15% of the heat transfer. Zone C is a vortex zone, where the fluid rotates in place or remains stationary, so it is also called the "heat transfer dead zone". In other words, 25 to 30% of the equipment capacity is not fully utilized. In addition, the tube bundle of this structure is also prone to vibration damage. According to tests, this damage is mainly caused by the baffle span being too large and the fluid flow velocity being too high. Especially in modern production processes that require large flows and high flow rates, this vibration damage is more difficult to avoid. Many designers try to increase the natural frequency of the tube bundle to mitigate this damage. However, according to the formula fn=0.04944CnÖEJg/weL4 in the American heat exchanger standard TEMA, when the tube material and size are determined, the only parameter that affects the natural frequency fn is the baffle spacing L. To increase fn, you have to reduce the L value. In other words, the number of baffle plates should be increased. However, when the number of baffles increases, the shell side resistance increases, the energy consumption increases, the heat transfer dead zone increases, and the effective heat transfer area decreases. This post was last edited by prt0683 on 2009-3-22 07:27 ]

Simply put, the baffle rod uses four sets of round steel perpendicular to the heat exchange tube to form a tic to fix the heat exchange tube. The fluid and the heat exchange tube form a downstream flow, but the baffle rod will cause the fluid to continuously generate Karman vortices to improve the heat transfer efficiency. I have only seen this kind of structure before, but never designed it.

Most baffle rods are used in condensers with phase change. The effect in heat exchangers without phase change is not significant, and is even worse than that of arcuate plate heat exchangers. In order to facilitate manufacturing, various manufacturers have some changes in the support rods of the baffle rings.

I have never been exposed to tie-rod heat exchangers. I only know that the fluid flows in axial flow. When the Reynolds number is very low, it can achieve turbulent flow, and the vibration is smaller than that of the baffle plate, and the pressure drop is smaller.

I’ve never seen it and I don’t have any pictures or photos to post. Let’s take a look.