Pressure drop plate heat exchangers phe contribute to considerable energy savings both upstream and downstream in many different hydrocarbon processes, but whatever the application, there is one characteristic that they nearly all share. Selection of heat transfer models and fouling coefficients for shell side and tube side. Radiant floor heating boiler page 2 radiant floor heating water heater page 2 domestic hot water page 3 snow melt page 3 brazetek heat exchangers 2276 homecrest ave, suite 4d brooklyn, ny 11229 tel 7188740197 fax. To make the most of exchanger design software, one needs to understand sthe classi. The interpretation of relation 2 is that if the velocity, for example, is doubled, the pressure drop is increased four times. Excessive pressure drop is of course negative, because the flow must then be pushed through the bphe using a lot of pump power. The heat transfer requirements clearly have to be met in the design of any phe and the way this is done depends on the relative importance placed on cost, physical size and pressure drop. This means that the plate heat exchanger can also be dismantled for cleaning and maintenance. Jul 25, 2003 extended surface heat exchanger pressure drop.
Saffari and others published optimization of heat transfer and pressure drop for a spiralwound heat exchanger due to. A plan for increasing heat exchanger performance for shell and tube exchangers should consider the following steps. Numerical investigation of the effect of baffle orientation on heat transfer and pressure drop in a shell and tube heat exchanger with leakage flows. Karahalios 1990 and petrakis and karahalios, 1996, petrakis and karahalios, 1997, petrakis and karahalios, 1999 reported the fluid flow and heat transfer in. A theoretical model that predicts the thermal and fluidic characteristics of a micro crossflow heat exchanger is developed in this study. The heat exchanger designs must balance between heat exchanger effectiveness and pressure drop to achieve the desired. Hello friends,i am designing a plate and frame heat exchanger phe. Pressure drop is a phenomenon with both positive and negative consequences for the heat transfer process. The stack of heat transfer plates and gaskets is clamped together with bolts in a frame. The results indicate that the unbaffled geometry provides nearly the same heat transfer with only 20 to 25% of the pressure drop penalty in the reynolds number range of interest. Therefore, this study describes the theoretical relationship between the heat transfer performance of heat exchangers, including the pressure drop and power output from the heat engine of otec, and proposes a comprehensive performance evaluation index. By forcing the fluids through the heat exchanger at higher flow rates, the overall heat transfer coefficient u value might be increased, but this also. Selection of heat exchanger tema layout and number of passes.
That the ua value overall heat transfer coefficient, u, multiplied by the heat transfer area, a of the heat exchanger is a constant value. Baffle spacing is increased when it is necessary to decrease pressure drop. The theoretical model is validated by comparing the theoretical solutions with the experimental data from the. This short article assumes that you are in a simulation stage and have already calculated both shell side pressure drop and. The maximum temperatures used for sealing heat exchangers are. Basic heat exchanger performance evaluation method on otec. Computational analysis of helical coil heat exchanger for. The selection of a heat exchanger depends on many factors including capital and operating costs, fouling, corrosion tendency, pressure drop, temperature.
If the pressure drop is acceptable, then the overall heat transfer coefficient u could be reestimated for this heat exchanger configuration. Tutorial heat exchanger shell side pressure drop calculation. Tube side pressure drop is calculated using the same pipe flow factors developed in your fluid mechanics class. Pressure drop calculation for shell and tube and double pipe. Heat transfer and pressure drop in crossflow welded plate. Gaskets, in addition to their sealing effect, serve to direct the flow of the fluids, and are placed along the grooves at the edges of the plates.
Pdf heat transfer and pressure drop characteristics of multi tubes. Heat exchanger pressure drop analysis fundamentals of heat. Olson chemical engineering division national institute of standards and technology boulder, co 803033328 we have measured the heat transfer and pressure drop characteristics of a novel, compact heat exchanger in. Plate heat exchangers were first produced in the 1920s and have since been widely used in a great number of sectors a plate exchanger consists of a series of parallel plates that are placed one above the other so as to allow the formation of a series of channels for fluids to flow between them. As a rule of thumb, start with 10 psi on both the shellside and the tubeside. This short article assumes that you are in a simulation stage and have already calculated both shell side pressure drop and tube side pressure drop. Lewin heat exchanger design tube pressure drop pressure drop of the fluid flowing in the tubeside of a heat exchanger is given by the darcy formula. Heat transfer and pressure drop correction factors based on the belldelaware method have been compared for an optimized segmental baffle heat exchanger and a helical baffle heat exchanger. Optimisation of plateplatefin heat exchanger design. Correcting flaws in construction and piping that may have a detrimental effect on heat transfer and pressure drop may be the solution. As a guide, allowable pressure drops between 20 and. Optimisation of plateplate fin heat exchanger design kunpeng guo the university of manchester 2015 abstractphd thesis with increasing global energy consumption, stringent environmental protection legislation and safety regulations in industrialised nations, energy saving has been put under high priority.
In the phe the plates create a frame where the plates are pressed with headers and tie bars, and the seal is guaranteed by gaskets. Reduced heat transfer and increased pressure drop under fouled conditions can have significant implications for energy utilization on the process plantnamely reduced heat recovery that may have to be made good using primary energy, and increased energy requirements for monitoring the fluid through the exchanger. Shellandtube heat exchangers rajiv mukherjee, engineers india ltd. Since cryocooler designers are usually interested in the overall pressure drop of the heat exchanger, rather than the specific local core friction pressure drop, it is useful and informative to understand how the overall pressure drop is distributed along the heat exchanger assembly. The amount of pressure drop on the shellside is a function of baffle spacing, baffle cut, and baffle type. That the pressure drop across any side of the heat exchanger can be computed a k value, representing flow resistance defined in eq. The tubeside pressure drop across an exchanger increases due to fouling i changing the roughness of the fluidtube interface. The plates are fitted with a gasket which seals the interplate. Different types of heat exchangers are shown in figure 42. Optimisation of plateplatefin heat exchanger design kunpeng guo the university of manchester 2015 abstractphd thesis with increasing global energy consumption, stringent environmental protection legislation and safety regulations in industrialised nations, energy saving has been put under high priority. The gages in widespread use in the heat exchanger and pressure vessel industries for hydrostatic procedkre to meet the code requirements are dial type bourdon tube gages.
Consequently, they produced the most detailed and useful work to date on a single shellandtube heat exchanger optimization. Pressure drop in plate heat exchanger posted in student. Pressure drop requirements for plate heat exchangers. The effect of heat transfer on the pressure drop through a heat exchanger for aero engine applications. Heat transfer and pressure drop in heat exchangers. All the inputs given in the sample problem statements are given to the calculator and pressure drop across the heat exchanger shell side is calculated as output. Pressure drop is a major constraint in thermal design of shell and tube heat exchangers. Gasketed plate heat exchangers hxxxliquid gasketed plate heat exchangers are particularly suitable for large fl ows and high cooling capacities.
Specification of tube parameters size, layout, pitch. Shell and tube heat exchangers basic calculations pdh online. Simulation has been done by varying the mass flow rate from 180 lph to 420 lph on different configuration of helical coiled tube. Heat exchangers jordan university of science and technology. Pdhonline course m371 2 pdh shell and tube heat exchangers. You will have to understand the process thoroughly before you can attempt to specify the pressure drop on each side of the heat exchanger. Optimization of thermal design requires maximization of overall heat transfer coefficient and.
The interpretation of relation 3 is that if the pressure drop, for example, is increased four times, the heat transfer coefficient becomes 4 1. Plate heat exchanger working principle, how a plate heat. Hydrotest procedure of all the turnarounds i remember, heat exchangers have always been tested with water. Pressure drop calculation for the shell side in shelland. Pdf the effect of heat transfer on the pressure drop. The result shows that the temperature drop and pressure drop are affected by geometry of helical coil heat exchanger. Pressure drop dependence on geometry and fluid properties. Plate heat exchanger phe is one of the modern types of compact heat transfer equipment, which can significantly enhance the heat recuperation and improve. Estimate the pressure drop across the heat exchanger. If the heat exchanger is very tall, it is also necessary to take into account the pressure drop due to change in elevation when calculating the total pressure drop. Three types of finned tubes were investigated where the fin height varies most. Heat transfer and pressure drop of gas coolers article pdf available in ashrae transactions 107.
This calculator uses the same basic steps discussed above and hence the answer also matches with the figure above 0. The frictional head losspressure drop calculations are part of a multistep, iterative preliminary heat exchanger design process. Heat transfer and pressure drop performance comparison of. It is referred to as a laminar flow heat exchanger if the surface area density is above about 3000 m2m 3 914 ft2ft3, and as a micro heat exchanger if the surface area density is above about 10,000 m2m 3 3050 ft2ft3. A tubeintube helical heat exchanger requires the knowledge of the heat transfer rates for the two flowing fluids, i. A thermal design of a shell and tube heat exchanger is meaningful only when it is optimum and the extent of the optimality is constrained by the pressure drop. Heat exchanger pressure drop analysis fundamentals of. The pressure drop calculated for double pipe heat exchangers is that for the flow inside the inner pipe, including both straight pipe friction losses and minor losses due to all of the 180 degree bends. Make a more detailed estimate of the overall heat transfer coefficient, u, based on the preliminary heat exchanger configuration.
Numerical simulation of heat transfer and pressure drop in. The influence of geometry on heat transfer and pressure drop. Pressure drop associated with fluid distribution elements. Any technical meeting between a process engineer and a heat exchange design specialist is likely to involve a discussion about. Pressure drop and heat transfer study in tubeintube. Finally, this study provides the first pressure drop data for gullwing baffling. Heat exchangers are an enabling technology for efficient power generation with a closed, recuperated brayton cycle using supercritical carbon dioxide sco 2 as the working fluid. A printed circuit heat exchanger pche is fabricated by diffusionbonding thin metal plates which were previously engraved with flow channels.
A ballpark estimate can be obtained by the relatively simple approach described below, which is given in a book by peters,timmerhaus, and west 1. Although no data are available in literature for multi. High pump power can be achieved only with large pumps, which demand a large amount of. Heat exchangers influence the overall system efficiency and system size. Denotes required fields fax completed form to 7188740198. Pressure drop characteristics of slittype heat exchanger. Koorosh mohammadi, wolfgang heidemann, hans mullersteinhagen. The selection of a heat exchanger depends on many factors including capital and operating costs, fouling, corrosion tendency, pressure drop, temperature ranges, and safety issues tolerance to leakage. If it is possible to increase the allowable pressure drop, and incidentally accept higher pumping costs, then the heat exchanger will be smaller and less expensive. Pressure drop in heat exchangers is an important consideration during the design stage.
Tube side pressure drop is calculated using the same pipe flow factors developed in. Managing pressure drop in the design of shell and tube heat. The plate heat exchanger consists of a pack of corrugated metal plates with portholes for the passage of the two fluids between which heat transfer will take place. If there is a pump upstream of the heat exchanger, there probably will be no concern about pressure drop as. Setting shell side and tube side pressure drop design limits. In this thesis work, numerical simulation is used to investigate the heat transfer and pressure drop in plate heat exchangers, with the intention of determining the effect of channel geometry and flow conditions on the heat transfer of the exchangers. Heat transfer and pressure drop in a compact pinfin heat exchanger with pin orientation at 18 to the flow direction douglas a. According to standard performance limits for alphalaval phe, the pressure drop is 30 kpa per ntu. If an exchanger has 200 tubes in 2 passes, the total flow will be moving through 100 tubes at a time.
If it is too high, revise the heat exchanger configuration until the pressure drop is acceptable. The frictional head loss pressure drop calculations are part of a multistep, iterative preliminary heat exchanger design process. A tube in tube helical heat exchanger requires the knowledge of the heat transfer rates for the two flowing fluids, i. That the heat exchanger is a lumped parameter model. The problem with their method however, is that it is restricted to. In addition, the repeated changes in direction caused by the numerous passes in the tubes adds additional. Pdf optimization of heat transfer and pressure drop for a spiral. Pressure drop calculation for shell and tube and double. This is a quick guide on how to adjust the pressure drops in shell and tube heat exchangers. This book also provides much valuable information on the design of such heat exchangers, including more sophisticated methods of estimating the pressure drop. The plate pack is assembled between a fix frame plate and a movable pressure plate and compressed by tightening bolts. Therefore, this study describes the theoretical relationship between the heat transfer performance of heat exchangers, including the pressure drop and power output from the heat engine of otec, and proposes a comprehensive performance evaluation. Managing pressure drop in the design of shell and tube.