Design and Analytical Investigation of a Parallel-Flow Plain Shell-Pipe Heat Exchanger Considering Pressure Losses

A first-principles heat exchanger model, incorporating both heat transfer correlations and phase change effects, was developed with particular emphasis on simulating a flooded evaporator commonly used in water-cooled chillers. The governing partial differential equations were discretized according to the exchanger geometry and numerically solved using the finite difference approach. Phase change of the refrigerant was described through complementarity constraints. Model performance was evaluated across a range of parameter settings, including an optimization task derived from the detailed exchange simulation. Experimental validation was conducted using (1.5 m) test tubes with two inlet/outlet configurations (0.02/0.025 m and 0.025/0.03 m) for both flow orientations. Water served as the working fluid, heating cold air from (18 °C) to (52 °C) in a counterblow double-pipe heat exchanger and producing hot water up to (86 °C). So as to calculate the thermal achievement of a counter- inflow double-pipe heat exchanger, the empirical conditions contained divergence in the mass inflow rates of the cold and warm liquids. In particular, the warm water stream's mass inflow rate was independently changed among ("0.09" ) and ("0.20" ) kg s⁻¹, while the cold air stream's mass inflow rate was methodically varied among ("0.01" ) and ("0.03" ) kg s⁻¹. In these situations, the heat exchanger ("HE" ) could an important increase in the cold air stream's temperature, from an inlet amount of ("18 °C" ) to a top outlet temperature of approximately ("52 °C" ), employing water as the working liquid on the warm part. As a consequence, the warm water stream touched temperatures as great as ("86 °C" ), representing effective thermal energy exchange ("ETEE" ) internal the apparatus. The average temperature across the exchanger was approximately (40.7 °C). Additionally, the extent of the transitional flow regime was examined by analyzing turbulence development under all experimental conditions. The Reynolds numbers for cold air and hot water were in the ranges of ("30470–29320" ) to ("6313–6327.4" ), ("60964.7–59783" ) to ("7014.43–7028.8" ), and ("91459.3–90267" ) to ("14028.6–14043" ), respectively. Turbulent flow conditions were employed throughout all experimental tests. The computational aspect of the study was conducted using Microsoft Excel, in which more than (5,199 heat transfer equations were implemented. The finite difference method was applied to evaluate the thermophysical properties of each working fluid based on fluid temperature, using iterative calculation techniques.