Chemical & Process Engineering / Double-Pipe Heat Exchanger
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LABORATORY 10 · CHEMICAL & PROCESS ENGINEERING

Concentric Double-Pipe Heat Exchanger Co-Current vs Counter-Current Thermal Duty

Evaluate the thermal duty q and overall heat transfer coefficient U of a concentric double-pipe heat exchanger under co-current and counter-current flow configurations as a function of cooling water flow rate. Explore interactive transport phenomena, unit operations simulation, and chemical engineering telemetry.

TRANSPORT PHENOMENA · UNIT OPERATIONS · PROCESS CONTROL · REACTION ENGINEERING

Your virtual chemical and process engineering laboratory.

COUNTERCURRENT THERMAL DUTY Q—
PROCESS & PILOT PLANT TELEMETRY

Ready to sample with Cooling Flow V_c = 9.0 L/min.

9.0 L/min
Process Fluid: Standard industrial test fluid at 20.0 °C

Adjust Cooling Flow V_c, then execute chemical process trial.

Chemical and process engineering telemetry is evaluated rigorously using 64-bit IEEE 754 precision. Residuals reflect ordinary least-squares regression across successive observations. Continuous data structures support high-fidelity transport phenomena and unit operations modeling.

Process engineering assumptions and boundary condition limits

The transport and thermodynamic models apply within the specified calibrated operating window (3.0 to 18.0 L/min). Evaluated using a 2.0 m copper inner tube (ID 15.0 mm, OD 17.0 mm) inside a 28.0 mm ID PVC shell (heat transfer area A = 0.1068 m^2). Linear model relates counter-current thermal duty q directly to cooling water flow rate V_c.

Process apparatus & industrial sensors.

Concentric Double-Pipe Heat Exchanger Spool

2.0 m long copper inner tube (OD 17 mm) inside outer clear PVC jacket (ID 28 mm).

Flow Reversal Valve Manifold

Four-way ball valve array allowing instantaneous switching between co-current and counter-current modes.

Constant-Temperature Hot Water Loop

Delivers inner-tube hot water at 60.0 ± 0.1 °C and constant flow rate of 10.0 L/min.

Precision Variable-Area Utility Rotameter

Meters annulus cooling water flow V_c from 2.0 to 20.0 L/min with ±0.1 L/min accuracy.

Four-Channel Digital RTD Thermocouple Array

Logs T_h,in, T_h,out, T_c,in, and T_c,out with 0.05 °C resolution at exchanger terminals.

Differential Pressure Transmitter

Monitors annular and tube-side hydraulic pressure drops across the 2.0 m length.

FOLLOW THE METHOD

A reason behind every step.

Evaluate the thermal duty q and overall heat transfer coefficient U of a concentric double-pipe heat exchanger under co-current and counter-current flow configurations as a function of cooling water flow rate. Standardized parameter settings: 3.0, 6.0, 9.0, 12.0, 15.0, 18.0 L/min.

01

Flow Configuration & Manifold Alignment

Configure the valve manifold for counter-current flow; start the hot water pump at 10.0 L/min (60.0 °C) and cold water at 9.0 L/min (15.0 °C) for 10 minutes to reach steady state.

02

Hot Water Baseline Verification

Verify inner-tube hot water flow is constant at 10.0 L/min and inlet temperature stable at 60.0 ± 0.1 °C.

03

Initial Cooling Flow Plateau

Adjust annulus cooling water flow rate to V_c = 3.0 L/min; allow thermal equilibrium and record all four terminal temperatures.

04

Thermal Duty Calculation & Heat Balance

Calculate heat gained by cold water q_c and heat lost by hot water q_h, ensuring closure within 3%.

05

Flow Rate Progression Protocol

Step cooling water flow through 6.0, 9.0, 12.0, 15.0, and 18.0 L/min, logging terminal temperatures and calculating LMTD at each step.

06

Thermal Duty Linear Regression

Plot counter-current thermal duty q versus cooling flow rate V_c, fitting a linear regression through the origin to determine sensitivity S.

YOUR NOTEBOOK · 0 OBSERVATIONS

Turn measurements into chemical process engineering insight.

See a complete example report ↗

Points are your recorded observations. The solid regression line validates Double-Pipe Heat Exchanger mathematical scaling.

LINEAR REGRESSION FIT · y = mx + b
q = S · V_c = 0.4200 · V_c
#Annulus Cooling Water Flow V_c (L/min)Countercurrent Thermal Duty q (kW)Cooling water flow rate V_c (L/min)Countercurrent thermal duty q (kW)Remove

No readings yet. Execute a process trial and record it.

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CHECK YOUR UNDERSTANDING

Explain what the process engineering metrics mean.

In a co-current (parallel) heat exchanger, the outlet temperature of the cold fluid can:

The hydraulic diameter D_h for the annular passage between pipes of diameters D_2 (outer) and D_1 (inner) is:

For a given heat exchanger area and inlet temperatures, the heat transfer rate in counter-current flow compared to co-current flow is:

In a double-pipe heat exchanger, adding longitudinal fins to the outside of the inner tube is beneficial when:

THEORY AND UNIT OPERATIONS CONTEXT

Process engineering background & physical principles.

The concentric double-pipe heat exchanger represents the simplest, most fundamental tubular heat transfer device, consisting of one pipe positioned coaxially inside a larger pipe. Fluid 1 flows through the inner tube, while Fluid 2 flows through the annular space between the two pipes. Because of its straightforward geometry, it provides an ideal platform for directly comparing co-current (parallel) and counter-current flow arrangements. In co-current flow, both hot and cold fluids enter at the same end and travel in the same direction; the maximum attainable exit temperature of the cold stream is thermodynamically limited by the hot fluid exit temperature. In counter-current flow, the fluids enter at opposite ends and flow in reverse directions, maintaining a favorable, nearly uniform temperature difference throughout the exchanger length, enabling the cold outlet temperature to surpass the hot outlet temperature. Thermal duty q transferred between streams is governed by the enthalpy balance: q = m_dot_c · c_p,c · (T_c,out - T_c,in) = U · A · ΔT_lm. In this laboratory experiment, a 2.0-meter double-pipe heat exchanger is operated with hot water in the inner tube and cooling water in the outer annulus across flow rates from 3.0 to 18.0 L/min to quantify the linear thermal duty sensitivity S and compare co-current vs counter-current heat recovery.

q = S · V_c = 0.4200 · V_c

Evaluated using a 2.0 m copper inner tube (ID 15.0 mm, OD 17.0 mm) inside a 28.0 mm ID PVC shell (heat transfer area A = 0.1068 m^2). Linear model relates counter-current thermal duty q directly to cooling water flow rate V_c.