Computer aided design of plate heat exchangers

Chemical Engineering Transactions, 2009

The optimal design for multi-pass plate-and-frame heat exchanger with mixed grouping of plates is considered. It is formulated as the mathematical problem of finding the minimal value for implicit nonlinear discrete/continues objective function with inequality constraints. The optimizing variables include the number of passes for both streams, the numbers of plates with different corrugation geometries in each pass, the plate type and size. To estimate the value of objective function in a space of optimizing variables the mathematical model of plate heat exchanger developed. To account for thermal and hydraulic performance of channels between plates with different corrugation patterns, the exponents and coefficients in formulas to calculate heat transfer coefficients and friction factors used as model parameters. The procedure and software for numerical experiment to identify model parameters by comparing the calculation results with those obtained with free available in web computer programs of plate manufacturers is developed. The sets of such parameters are obtained for a number of industrially manufactured plates. The described approach implemented as software for plate heat exchangers calculation. Two case studies results discussed.

2015

In the present paper the design of plate heat exchangers<br> is formulated as an optimization problem considering two<br> mathematical modelling. The number of plates is the objective<br> function to be minimized, considering implicitly some parameters<br> configuration. Screening is the optimization method used to solve the<br> problem. Thermal and hydraulic constraints are verified, not viable<br> solutions are discarded and the method searches for the convergence to<br> the optimum, case it exists. A case study is presented to test the<br> applicability of the developed algorithm. Results show coherency with<br> the literature.

International Journal of Heat and Mass Transfer, 2004

A screening method is presented for selecting optimal configurations for plate heat exchangers. The optimization problem is formulated as the minimization of the heat transfer area, subject to constraints on the number of channels, pressure drops, flow velocities and thermal effectiveness, as well as the exchanger thermal and hydraulic models. The configuration is defined by six parameters, which are as follows: number of channels, numbers of passes on each side, fluid locations, feed relative location and type of channel flow. The proposed method relies on a structured search procedure where the constraints are successively applied to eliminate infeasible and sub-optimal solutions. The method can be also used for enumerating the feasible region of the problem; thus any objective function can be used. Examples show that the screening method is able to successfully determine the set of optimal configurations with a very reduced number of exchanger evaluations. Approximately 5% of the pressure drop and velocity calculations and 1% of the thermal simulations are required when compared to an exhaustive enumeration procedure. An optimization example is presented with a detailed sensitivity analysis that illustrates the application and performance of the screening method.

2014

For many industrial applications plate heat exchangers are demonstrating a large superiority over the shell and tube and other types of heat exchangers. In this paper we design a copper plate heat exchanger for milk pasteurization in a food industry using high temperature in a short time. The efficiency of this device depends on numerous factor likes space requirement, material required for construction, pressure drop.Energy requirement for circulation of milk and water by pump. In this paper we present a theoretical analysis of counter flow copper plate type heat exchanger and result and CFD analysis of pressure drop for milk and water over plate heat exchange .The result of CFD validate results predicted theoretically. Knowing the hot and cold fluid stream inlet and outlet temperatures and mass flow rates of hot and cold fluid and respective heat capacities, and values of heat transfer coefficient. Mathematical model based on steady flow energy balancing for specific heat exchanger geometry and operational parameters the problem is numerically solved by LMTD method. This paper, present modeling done by PROE, CATIA V5R19, and the software analysis prediction of pressure drop and thermal analysis of plate heat exchanger done by CFD tools. CFD prediction are also validate with theoretical analysis of plate heat exchanger.

The developments in design theory of plate heat exchangers, as a tool to increase heat recovery and efficiency of energy usage, are discussed. The optimal design of a multi-pass plate-and-frame heat exchanger with mixed grouping of plates is considered. The optimizing variables include the number of passes for both streams, the numbers of plates with different corrugation geometries in each pass, and the plate type and size. To estimate the value of the objective function in a space of optimizing variables the mathematical model of a plate heat exchanger is developed. To account for the multi-pass arrangement, the heat exchanger is presented as a number of plate packs with co-and counter-current directions of streams, for which the system of algebraic equations in matrix form is readily obtainable. To account for the thermal and hydraulic performance of channels between plates with different geometrical forms of corrugations, the exponents and coefficients in formulas to calculate the heat transfer coefficients and friction factors are used as model parameters. These parameters are reported for a number of industrially manufactured plates. The described approach is implemented in software for plate heat exchangers calculation.

A plate heat exchanger is a type of heat exchanger that uses metal plates to transfer heat between two fluids. This has a major advantage over a conventional heat exchanger in that the fluids are exposed to a much larger surface area because the fluids spread out over the plates. This facilitates the transfer of heat, and greatly increases the speed of the temperature change. The plate heat exchanger (PHE) is a specialized design well suited to transferring heat between medium- and low-pressure fluids. Welded, semi-welded and brazed heat exchangers are used for heat exchange between high-pressure fluids or where a more compact product is required. The hot fluid flows in one direction in alternating chambers while the cold fluid flows in true counter-current flow in the other alternating chambers. The heat transfer surface consists of a number of thin corrugated plates pressed out of a high grade metal. The pressed pattern on each plate surface induces turbulence and minimizes stagnant areas and fouling. Unlike shell and tube heat exchangers, which can be custom-built to meet almost any capacity and operating conditions, the plates for plate and frame heat exchangers are mass-produced using expensive dies and presses. In this paper we designed the PHE for the required operating conditions. In the design we calculated the overall heat transfer coefficient of PHE. The heat transfer rate and the number of plates required for the PHE were also calculated. Cost optimization of the designed PHE was carried out and it has been found that there is a considerable drop in the cost of the heat exchanger.

A mathematical model is developed in algorithmic form for the steady-state simulation of gasketed plate heat exchangers with generalized configurations. The configuration is defined by the number of channels, number of passes at each side, fluid locations, feed connection locations and type of channel-flow. The main purposes of this model are to study the configuration influence on the exchanger performance and to further develop a method for configuration optimization. The main simulation results are: temperature profiles in all channels, thermal effectiveness, distribution of the overall heat transfer coefficient and pressure drops. Moreover, the assumption of constant overall heat transfer coefficient is analyzed.

Plate heat exchangers are very important equipments used in industrial applications. The paper presents an analysis related to the influence of the number of plates on the performance of a heat exchanger. 3D models are made for eight cases and using finite element method are performed numerical simulations of fluid flow distribution. Numerical results are presented for 1 pass-1pass counter-flow plate heat exchanger.

Heat Transfer Engineering, 2021

Thermal design and analysis of heat exchangers are predominantly conducted considering constant heat transfer coefficients. However, these vary along the length and affect the calculations of heat transfer rates and area allocations. The current paper investigates the variations in the heat transfer coefficients in plate heat exchangers (PHX), using different numerical approaches. The heat transfer coefficient is calculated at the inlet, outlet, and systematically selected intermediate points for each method. The analysis is conducted for two different systems, i.e., a laboratory-scale and an industrial scale PHX at different chevron angles. It is concluded that the effect of the variable heat transfer coefficient is more significant for the large-scale heat exchanger due to high flow rates, geometrical specifications, Reynolds number, and thermophysical properties. The deviation of the local heat transfer coefficient along the heat exchanger length is approximately 9-14 % and 3-6% for industrial and laboratory scale PHX, while an area deviation of around 15% is observed.

Energy, 2013

The mathematical model of plate heat exchanger (PHE) is developed using decomposition of the plate on its main corrugated field, which cause major effect on heat transfer, and distribution zone, which influences mostly the hydraulic performance. Model is validated on experimental data for some commercial plates. It is shown, that for specified pressure drop, temperature program and heat load the geometrical parameters of plate and its corrugations, which are enable to make PHE with minimal heat transfer area, can be found. The developed mathematical model can be used for designing of plates with geometry, which is in the best way satisfying process conditions of the certain specific range. The case study for conditions of PHE application in District Heating systems is presented.