Basic Pulse Tube Refrigerator Research Articles

Acoustic impedance measurements of pulse tube refrigerators

Complex acoustic impedance is determined in a prototype refrigerator that can mimic orifice-type, inertance-type, and double inlet-type pulse tube refrigerators from simultaneous measurements of pressure and velocity oscillations at the cold end. The impedance measurements revealed the means by which the oscillatory flow condition in the basic pulse tube refrigerator is improved by additional components such as a valve and a tank. The working mechanism of pulse tube refrigerators is explained based on an electrical circuit analogy.

Three-dimensional numerical simulation of the basic pulse tube refrigerator

A three-dimensional physical and numerical model of the basic pulse tube refrigerator (PTR) was developed. The compressible and oscillating fluid flow and heat transfer phenomenon in the pulse tube were numerically investigated using a self-developed code. Some cross-section average parameter variations such as velocity, temperature and pressure wave during one cycle were revealed. The variations of velocity and temperature distributions in the pulse tube were also analyzed in detail for further understanding of the working process and refrigeration mechanism of PTRs.

C07 振動流中の熱伝達率に関する数値解析(パルス管冷凍機,熱音響機器及び関連要素と応用システム(3))

Numerical simulation of heat and fluid flow has been performed to clarify the effect of heat transfer coefficient on temperature change in oscillatory flows. Transient one-dimensional equations of continuity, momentum and energy are solved utilizing a TVD scheme. A basic pulse tube refrigerator is selected as the physical model. In this paper, we investigate the behavior of temperature changes during a cycle under various conditions of heat transfer coefficient. As a result, it was found that there are differences in temperature change among various conditions.

Numerical simulation of heat and fluid flow in basic pulse tube refrigerator

PurposeTo clarify the physical working principle of refrigeration in basic pulse tube refrigerators (BPTRs).Design/methodology/approachA numerical simulation was performed. Transient compressible NS equation was solved utilizing the TVD scheme coupled with energy equation.FindingsThe periodic flow and temperature field were obtained. The movement of the gas particles and heat transfer between the gas particles and wall were analyzed. These numerical results explained the mechanism of surface heat pumping (SHP) which is known as the working principle of refrigeration in BPTR.Research limitations/implicationsPulse tube refrigerator (PTR) is classified into the third generation. BPTR is the first generation. It is needed to clarify the working principle of refrigeration in the second and third generation by analyzing heat and fluid flow in the tube.Practical implicationsA very useful source of information to understand the physical working principle of refrigeration in BPTR.Originality/valueThe mechanism of SHP was shown by analyzing the heat exchange between the gas particles and pulse tube wall.

ベーシック型パルス管冷凍機における管壁の影響(パルス管冷凍機,熱音響機器及び関連要素と応用システム(2))

ベーシック型パルス管冷凍機における管壁の影響(パルス管冷凍機,熱音響機器及び関連要素と応用システム(2))

Numerical Analysis of Heat and Fluid Flow in Pulse Tube Refrigerator

A numerical study has been performed to analyze the working principle of refrigeration in basic pulse tube refrigerator. There is a mechanism called “surface heat pumping” as one of the working principles of refrigeration for basic pulse tube refrigerator of the first generation. This is the mechanism that heat is pumped from the cold end to the hot end by the successive heat exchange between the pulse tube wall and the working gas. Transient axisymmetric two-dimensional equations of continuity, momentum and energy were solved by means of TVD scheme. The transient behaviors of pressure and gas temperature, and heat transfer from the working gas to the tube wall are analyzed. Also the behavior of surface heat pumping is explained by analyzing the axial movements and temperature changes of gas particles.

D143 ベーシック型パルス管冷凍機の熱流動数値解析

D143 ベーシック型パルス管冷凍機の熱流動数値解析

D05 ベーシック型パルス管冷凍機における熱流動数値シミュレーション : パルス管管壁と作動ガスの熱移動に関する解析

Numerical simulation of viscous compressible flow in basic pulse tube refrigerator is conducted to make clear the working principle of refrigeration. Transient axisymmetric two-dimensional equations of continuity, momentum and energy were solved by means of TVD method. The physical model of the pulse tube with a regenerator is used for numerical simulation. Heat exchange between the pulse tube wall and the working gas in the pulse tube is assumed as a convective heat transfer. In this paper the transient behaviors of pressure and gas temperature, moving distances and temperature changes of gas elements in the pulse tube, and the effect on Surface Heat Pumping are analyzed.

B243 ベーシック型パルス管冷凍機における熱流動数値解析

B243 ベーシック型パルス管冷凍機における熱流動数値解析

D05 パルス管内の熱流動数値シミュレーション(パルス管冷凍機の解析)

Numerical simulation of viscous compressible flow in basic pulse tube refrigerator is conducted to clear the working principle of refrigeration. Transient axisymmetric two-dimensional equations of continuity, momentum and energy were solved by means of CIP method. The physical simulation model is a 10mm inner diameter and 50 mm length circular pulse tube containing a 10mm heat exchanger. The two models, adiabatic wall model and non-adiabatic wall model, were used for calculation. Some numerical results were obtained on the transient behaviors of pressure and temperature distributions and the two models were compared. Heat transfer between tube wall and fluid was analyzed in non-adiabatic model.

Entropy balance and performance characterization of the narrow basic pulse-tube refrigerator

The basic pulse-tube refrigerator is studied using near-isothermal theory. The theory has been extended to include evaluation not only of the enthalpy flux, but also of entropy. This allows for dividing the enthalpy flux into heat and work at the extremities of the tube, and as a result, the pulse-tube performance can be determined. Except for a simple numerical integration, this study proceeds entirely in closed form, so that an investigation of the complete parameter space can be performed fairly easily. Since the device is inherently irreversible, the coefficient of performance is limited to values lower than the Carnot limit, and the results show that coefficients of performance up to about 50 % of the limit are possible, but for relatively small temperature differences, outside of the cryogenic range. Still, in the usual arrangement with regenerator, a properly designed basic pulse-tube, with high-pressure amplitude and a suitable ratio between the volume of the tube and the volume of the cooler or reservoir, may conceivably remain competitive with the orifice-type device, in which, in contrast with the basic pulse-tube, an adiabatic loss at the cold end is unavoidable.

Analysis of basic pulse-tube refrigerator with regenerator

A previously presented thermodynamic analysis of the basic pulse-tube refrigerator is extended to the case with a regenerator. In this case there is a heat exchanger at the warm end of the regenerator, in addition to the cold and warm heat exchangers at the ends of the pulse tube. The analysis is based on a four-step cycle: adiabatic compression of the gas in the pulse tube; isobaric heat transfer from the gas to the wall of the pulse tube; adiabatic expansion of the gas in the pulse tube; and isobaric heat transfer from the wall of the pulse tube to the gas. The pressure is taken to be uniform during the entire cycle. Gas elements inside the regenerator are assumed to be at the local temperature of the regenerator. The performance of the regenerator and its adjacent heat exchangers is investigated using control volume analysis to determine enthalpy flows, and by control mass analysis to determine heat flows associated with individual gas elements. The mechanism by which heat is transported from the cold end to the warm end of the regenerator is discussed. The addition of the regenerator is found to yield significant improvements in the heat removed per cycle, the coefficient of performance and the refrigeration efficiency. Detailed results for these quantities are presented as a function of the temperature ratio of the heat exchangers.

Thermodynamic analysis of the basic pulse-tube refrigerator

The basic pulse-tube refrigerator is modelled as a tube with one end closed and with a movable piston at the other end. Both ends contain heat exchangers. The piston is capable of moving through the heat exchanger at its end. The thermodynamic model consists of four steps: adiabatic compression of the gas in the pulse tube; isobaric heat transfer from the gas to the wall of the pulse tube; adiabatic expansion of the gas in the pulse tube; and isobaric heat transfer from the wall of the pulse tube to the gas. During the entire cycle the pressure is taken to be uniform, and the gas inside either heat exchanger is assumed to be at the temperature of that exchanger. Upon neglecting gas motion during the isobaric heat transfer steps, complete analytical results are obtained for the temperature profiles of the wall, of the gas after compression, and of the gas after expansion. Each of these profiles is piecewise adiabatic. The profiles are used in finding the coefficient of performance and the net work done per cycle. The coefficient of performance is derived by noting that the basic heat transfer process consists of several reverse Brayton cycles, staged in series. The net work done per cycle is found by constructing the p-V diagram for the piston. This diagram represents a modified reverse Brayton cycle, with each of the compression and expansion steps consisting of two hyperbolic segments. The parameters determining these segments depend on the temperature at which gas enters the heat exchangers. Results are presented for the coefficient of performance and the heat removed per cycle as a function of the temperature ratio of the heat exchangers, for various values of the pressure ratio π and the non-dimensional length L h of the heat exchanger at the closed end. The model is non-linear and permits study of the effect of large values of π and L h.