DESIGN & FABRICATION AND HEAT TRANSFER ANALYSIS OF DOUBLE PIPE HEAT EXCHANGER

A double pipe heat exchanger consists of a pair of pipes (tubes) one positioned concentrically within the other. Double pipe heat exchangers are often connected in series to provide an increased heat transfer surface. They may be connected to have a parallel flow arrangement to handle large process steam flow. The inner pipe is often finned. The double pipe heat exchanger is adopted for low flow rate, high temperature and high- pressure application. These types of heat exchangers found their applications in heat recovery processes, air conditioning and refrigeration systems, chemical reactors, and food and dairy processes. The double pipe heat exchanger would normally be used for many continuous systems having small to medium head duties. The double pipe heat exchanger is used in industry such as condenser for chemical process and cooling fluid process. A lot of research has been done on the design and analysis of a double pipe heat exchanger. From the experimental results it is concluded that at higher flow rate i.e. 8 LPM all the parameters for both the flow arrangement are same. LMTD, Overall heat transfer coefficient, Average heat transfer, Heat transfer from hot and cold water all these parameters’ values are same for 8 LPM flow rates for both parallel and counter flow arrangements. In this CFD analysis of tube in tube heat exchanger we found that hot fluid gets cool down and cold fluid gets heated up to 3ᵒC in the counter flow study and for parallel flow study the difference is 2 to 2ᵒC. As we increase the number of iterations the solution gets converge and it will give more accurate results but if we use 500 iterations the temperature difference is less for both the flow.