Heat exchangers are the most important equipment in refrigeration processes. Design and modeling of heat exchangers operating at low temperatures are different from other regular heat exchangers. This study includes two sections. In the first section, design and modeling considerations needed for evaluating the real thermal behavior of heat exchangers at low temperatures were discussed. The...

An analytical model for a condenser with a wetted surface is developed by applying the governing conservations and rate equations and invoking the heat and mass transfer analogy. The heat exchanger is discretized in both the airflow and refrigerant-flow directions for a cross-flow configuration. Axial conduction along the tube walls is neglected and uniform distribution of water is assumed at t...

If an air flow is injected into a liquid fluid, many ambulant air bubbles are formed inside the fluid. Air bubbles move inside the liquid fluid because of the buoyancy force, and the mobility of these air bubbles makes sizable commixture and turbulence inside the fluid. This mechanism was employed to enhance the heat transfer rate of a horizontal double pipe heat exchanger in this paper. Howeve...

The water-cooled heat exchanger is one of the key components in a pulse tube refrigerator. Its heat exchange effectiveness directly influences the cooling performance of the refrigerator. However, effective heat exchange does not always result in a good performance, because excessively reinforced heat exchange can lead to additional flow loss. In this paper, seven different water-cooled heat ex...

In a shell and tube heat exchanger, the failure of tube-to-tubesheet welds results in high-pressure water jet which erodes the refractory in front of the tubesheet. Finite element method was employed to simulate the welding process and post weld heat treatment (PWHT) to find the factors affecting the failure in tube-to-tubesheet weldments. Residual stresses in two different geometries of tube-t...

The tube to tube sheet welding joints of heat exchanger is the most critical joints. A special Nondestructive testing technology was proposed, which is based on the digital radiographic imaging automatic inspection system to the characteristics on the tube to tube sheet welding joints of heat exchanger. A new style Linear Diode Arrays as a device is used to receive ray, which will be fixed on a...

A multi-tube, spirally-wound, cryogenic heat exchanger, the main heat exchanger (MHE) is the principal piece of heat-transfer equipment in mixed-refrigerant liquefaction cycles for producing liquefied natural gas (LNG). An MHE unit operation model called the spirally-wound tube-bundle module was developed as an integral component of the dynamic simulation capabilities for a process modeling pac...

Heat exchanger is a universal process equipment, which widely used in chemical industry, oil refining, thermal power and other industries. Shell-and-tube heat exchangers often fail prematurely due to flow-induced vibration. In this paper, aiming at the problem of severe vibration shell-and-tube an enterprise, acceleration sensors are measure shell tube side exchanger. Through analysis measureme...

Helical coil heat exchangers are widely used in industrial applications ranging fromcryogenic processes, air-conditioning, and nuclear reactors to waste heat recovery due totheir compact size and high heat transfer coefficient. In this kind of heat exchangers, flowand heat transfer are complicated. This paper reports a numerical investigation of theinfluence of different parameters such as coil...

heat exchangers (STHEs) is done by sophisticated computer software. However, a good understanding of the underlying principles of exchanger design is needed to use this software effectively. This article explains the basics of exchanger thermal design, covering such topics as: STHE components; classification of STHEs according to construction and according to service; data needed for thermal de...