Pressure Surge Research Articles

Parameter estimation of soft switch and influence of critical parameters on the performance of a valve controlled hydraulic drive system

This study presents a technique to estimate the parameter values of the soft switch, which can be used for reduction of pressure surge due to abrupt mode shift or speed reversal in high pressure hydrostatic transmission. The estimation of critical parameters is essential for component design and fabrication thereafter. Different hydraulic systems should have different parameter values of the soft switch. It depends on the developed pressure in the switched volume and valve transition time. The throttling energy loss of an on/off valve controlled hydraulic system is influenced by different component parameters of the soft switch, which has also been investigated in this work.

Dynamics of a dry-rebounding drop: observations, simulations, and modeling

Abstract Dynamics of a dry-rebounding drop was studied experimentally, numerically, and theoretically. Experimental results were reproduced by our computational fluid dynamics simulations, from which time series of kinetic energy, potential energy, and surface energy were obtained. The time series of these energies quantitatively clarified the energy conversion and loss during the dry-rebound. These results were interpreted by using an imaginary spring model and a spherical harmonic analysis. The spring model explained the vertical deformation of the drop, however, could not completely explain the energy loss; the timings of the energy loss did not match. From a viewpoint of the spherical harmonic deformation of a drop, the deformation of the drop after the impact was found to be a combination of two vibrational motions. One of the two vibrational motions is an inertial motion derived from the free-fall and the another is a pressure-induced motion derived from a pressure surge due to the sudden stop of the bottom part of the drop at the impact. The existence of the pressure surge at the impact was confirmed in the simulated results. The pressure-induced motion resists the inertial motion and consequently dumps the kinetic energy of the drop.

Surfactant effect on air/water flow in a multistage electrical submersible pump (ESP)

The surfactant effect on ESP boosting pressure under air–water flow is studied in this paper. A two-phase flow loop comprising a 7.62 cm diameter stainless steel liquid loop and 1.25 cm diameter gas loop is built up to conduct experimental measurements. A radial-type ESP with 14 stages assembled in series is installed on the testing bench. Pressure ports are drilled at inter-stage to measure the stage-by-stage pressure increment. The surfactant, isopropanol (IPA) is injected to change the interfacial properties of working fluids. Experiments are carried out with mapping and surging test schemes to evaluate pump behaviors at different operational conditions. ESP pressure increment under single-phase water flow agrees well with the catalog curves. For mapping tests without surfactant injection, ESP performance suffers from a severe degradation as gas flow rate increases. High gas entrainment rate causes oscillations of liquid flow rate and pump boosting pressure, featured by the instabilities of ESP operations. A sudden drop of ESP pressure increment, termed as pressure surging, occurs at the critical inlet gas volumetric fraction (GVF). For a larger rotational speed, the critical GVF is higher. With surfactant injection, ESP boosting pressure improves significantly. At different GVFs, only mild degradation is observed. Pressure surging phenomenon disappears. Further, liquid flow rate and pump boosting pressure are more stable at high GVFs compared to experimental data without surfactant injection.

Diurnal blood pressure changes.

The definition of diurnal blood pressure changes varies widely, which can be confusing. Short-term blood pressure variability during a 24-h period and the dipping status of diurnal blood pressure can be captured by ambulatory blood pressure monitoring, and these metrics are reported to have prognostic significance for cardiovascular complications. Morning blood pressure surge also indicates this risk, but its effect may be limited to populations with specific conditions. Meanwhile, the combined use of conventional office blood pressure and out-of-office blood pressure allows us to identify people with white-coat and masked hypertension. Current home devices can measure nocturnal blood pressure during sleep more conveniently than ambulatory monitoring; however, we should pay attention to blood pressure measurement conditions regardless of whether they are in a home, ambulatory, or office setting. The relatively poor reproducibility of diurnal blood pressure changes, including the nocturnal fall of blood pressure, is another underestimated issue to be addressed. Although information on diurnal blood pressure changes is expected to be used more effectively in the future, we should also keep in mind that blood pressure levels have remained central to the primary and secondary prevention of blood pressure-related cardiovascular diseases in clinical practice.

Association of morning blood pressure surge with carotid intima-media thickness and cardiac dysfunction in patients with cardiac syndrome-X

Background & hypothesis: We hypothesized that exaggerated morning blood pressure surge, may contribute in cardiac dysfunction and arterial stiffness in patients with cardiac syndrome X. Thus we investigated the impact of morning blood pressure surge on cardiac function and carotid intima-media thickness in subjects with cardiac syndrome X.Methods: We studied patients with cardiac syndrome X using ambulatory blood pressure monitoring and investigated the association of morning blood pressure surge with carotid intima thickness, left atrial volume index and left ventricular filling (E/e'). Seventy patients with cardiac syndrome X were enrolled for the study and compared with 70 age and sex matched controls.Results: Patients with cardiac syndrome X were stratified based on the systolic morning blood pressure surge value of control subjects to patients with exaggerated blood pressure surge (n = 42) and those with normal morning blood pressure surge (n = 28). Basal heart rate (p < .05), high sensitive C-reactive protein (p < .01), left atrial volume index (p < .01), E/e' (p < .01); carotid intima-media thickness (p < .001) and percentage of detected plaque (p < .005) were significantly higher in patients with exaggerated morning blood pressure surge group than those with morning blood pressure surge group. Morning blood pressure surge was significantly correlated with carotid intima-media thickness, high sensitive C-reactive protein, left atrial volume index and E/e' ratio in patients with cardiac syndrome X. In multivariate analysis, exaggerated morning blood pressure surge was the only independent predictor of increased carotid intima-media thickness (OR = 2.379; p < .001), and diastolic dysfunction (OR = 2.464; p < .001) in patients with cardiac syndrome X.Conclusion: Our data suggest that excessive morning blood pressure surge is an independent predictor for arterial stiffness and diastolic dysfunction in patients with cardiac syndrome X.

The effect of depression on morning blood pressure surge in maintenance hemodialysis patients with hypertension

Objective To investigate the effect of depression on morning blood pressure surge (MBPS)in maintenance hemodialysis(MHD)patients with hypertension. Methods 67 MHD patients with hypertension were included in this study.All clinical data were collected, and ambulatory blood pressure monitor was used to monitor patient's blood pressure in 24 hours.Self-rating depression scale(SDS) was used to survey 67 MHD patients, and multivariable logistic regression was conducted to determine independent risk factors for morning hypertension in MHD patients with hypertension. Results There were 14 depression patients in non-morning hypertension group(35.0%), 18 depression patients in morning hypertension group(66.7%), and the difference was significant(χ2=6.479, P=0.011). In addition correlation analysis showed that age(r=0.027, P=0.044), 24 h systolic pressure(r=0.284, P=0.020), 24 h diastolic pressure(r=0.278, P=0.023), fasting blood-glucose (r=0.293, P=0.039), low-density lipoprotein cholesterol (r=0.345, P=0.016), and the standard score of SDS(r=0. 276, P=0.024) were significantly correlated with MBPS .Furthermore, multivariable logistic regression showed that the standard score of SDS(OR=1.101, 95%CI=1.018-1.191, P=0.016), 24 h diastolic pressure (OR=1.070, 95%CI=1.007-1.136, P=0.028)and fasting blood-glucose (OR=2.127, 95%CI=1.118-4.049, P=0.022)were independent risk factors for morning hypertension in MHD patients with hypertension(OR=1.101, 95%CI: 1.018-1.191, P=0.016). Conclusion Depression, 24 h diastolic pressure and fasting blood-glucose can increase the risk of morning blood pressure surge in patients with MHD hypertension. Key words: Depression; Maintenance hemodialysis; Morning blood pressure surge

Experimental investigation of fluid loss and cake thickness control ability of zirconium (IV) oxide (Z_R O_2) nanoparticles in water based drilling mud.

A major technical and economical concern of the oil well drilling industry is the potential damage to productive formations because of excessive drilling fluid filtration and its multiplier effect on cake thickness. High fluid loss (high cake permeability) results in thick filter cake which reduces the effective diameter of the hole (tight holes) and causes various problems such as excessive torque when rotating the pipe, excessive drag when pulling it and high swab and surge pressures due to reduced hole diameter and differential pipe sticking due to increase in pipe contact.It is in this light that the potential of Zirconium (IV) oxide (Z_r O_2) nanoparticles in combating excessive filtration problem in Water Based Mud was investigated. Preliminary results show that addition of 0.50g (Z_r O_2) nanoparticle concentration brought about 19.10% reduction in fluid loss and 14.29 % reduction in cake thickness for the High Temperature/ High Pressure (HPHT) filtration test at 500psi and 250 OF. Similarly, the highest reduction of 48.31% and 38.10% in fluid loss and cake thickness respectively was achieved with addition of an optimum concentration of 2.0g of (Z_r O_2) nanoparticles for the HTHP filtration test at the same temperature and pressure.

Morning blood pressure surge: pathophysiology, clinical relevance and therapeutic aspects.

Morning hours are the period of the day characterized by the highest incidence of major cardiovascular events including myocardial infarction, sudden death or stroke. They are also characterized by important neurohormonal changes, in particular, the activation of sympathetic nervous system which usually leads to a rapid increase in blood pressure (BP), known as morning blood pressure surge (MBPS). It was hypothesized that excessive MBPS may be causally involved in the pathogenesis of cardiovascular events occurring in the morning by inducing hemodynamic stress. A number of studies support an independent relationship of MBPS with organ damage, cerebrovascular complications and mortality, although some heterogeneity exists in the available evidence. This may be due to ethnic differences, methodological issues and the confounding relationship of MBPS with other features of 24-hour BP profile, such as nocturnal dipping or BP variability. Several studies are also available dealing with treatment effects on MBPS and indicating the importance of long-acting antihypertensive drugs in this regard. This paper provides an overview of pathophysiologic, methodological, prognostic and therapeutic aspects related to MBPS.

Transient Pressure Surge in a Fluid‐Filled Fracture

Brief Report| March 20, 2018 Transient Pressure Surge in a Fluid‐Filled Fracture Yingcai Zheng Yingcai Zheng aDepartment of Earth and Atmospheric Sciences, University of Houston, 3507 Cullen Boulevard, Room 312, Houston, Texas 77204‐5007, yzheng12@uh.edu Search for other works by this author on: GSW Google Scholar Bulletin of the Seismological Society of America (2018) 108 (3A): 1481–1488. https://doi.org/10.1785/0120170230 Article history first online: 20 Mar 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Yingcai Zheng; Transient Pressure Surge in a Fluid‐Filled Fracture. Bulletin of the Seismological Society of America 2018;; 108 (3A): 1481–1488. doi: https://doi.org/10.1785/0120170230 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyBulletin of the Seismological Society of America Search Advanced Search Abstract Weak dynamic seismic stress waves from distant earthquakes can abruptly change the fluid permeability of a hydrologic system, trigger seismicity, or cause liquefaction. Many proposed mechanisms to explain these phenomena require a large fluid pressure gradient to induce fluid flow during the passage of the waves, yet the exact mechanism as to how the fluid pressure can change is unclear. Using full‐waveform numerical modeling, we found that the transient seismic‐wave pressure in a fluid‐filled fracture could increase more than 2 orders of magnitude relative to the incident pressure. We call this transient pressure surge (PS). This pressure increase could be much more pronounced for low‐frequency transient waves than for high frequencies and could develop a large pressure gradient to drive the fluid to flow. This PS phenomenon may be important for understanding many natural phenomena in fluid‐fracture systems. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

General hydro-geological impact of cleats on underground coal gasification

Potential aquifer contamination has been a huge environmental concern for the implementation of underground coal gasification (UCG) as coal seams are frequently overlaid by an aquifer. To explore the general impact of cleats on the mass transfer problems in UCG, particularly in the vertical direction, a dual-permeability (DP) cleat model was integrated into a 3-D numerical model which is dimensionally extensive to account for the hydrostatic effect of an aquifer. It was found that cleats favour UCG production, and the prime operational parameter, i.e., the injection pressure, plays a dominant role in governing vertical mass transport in UCG. Syngas production retains some constancy with variable geological settings unless a surge in the injection pressure occurs. Higher pressure injection generates higher peak rates but delayed production. At near-hydrostatic injection, gas species attain a weak presence in the overburden contrary to expectations based on key geological parameters. However, gas saturation in the cap rock increases appreciably under above-hydrostatic injection. The role of higher injection pressure becomes so overwhelming that variations or heterogeneity in geological parameters produce little difference in the transfer problems.

There is a significant relationship between morning blood pressure surge and increased abdominal aortic intima-media thickness in hypertensive patients.

There are limited data about increased aortic intima-media thickness (A-IMT) in the presence of subclinical target organ damage in hypertensive (HT) patients. In this study, we aimed to determine the frequency of increased A-IMT, the parameters determining increased A-IMT, and the relationship between increased A-IMT and other vascular IMT measurements. We prospectively included 265 patients (mean age 54.1 ± 10.6years, male/female 91/174) with essential HT. Physical examination of all patients was performed. Laboratory data and antihypertensive treatments were recorded. Twenty-four-hour ambulatory blood pressure monitoring (ABPM) was performed. Bilateral carotid, brachial, and femoral artery and abdominal A-IMT values were measured by B-mode ultrasonography (USG). Patients were categorized into two main groups: patients with increased A-IMT (≥ 3mm) or normal A-IMT (< 3mm). Increased A-IMT was detected in 55 patients (20.8%). There was a close relationship between increased A-IMT and advanced age, presence of coronary artery disease, high morning blood pressure surge (MBPS), and bilateral carotid and femoral IMT. Parameters associated with increased A-IMT in univariate analysis were assessed by regression analysis. Left femoral IMT and MBPS were independently associated with increased A-IMT. In the regression model, each 5-mmHg elevation in MBPS increased the risk of increased A-IMT by 34.2%. The cutoff value of MBPS obtained by the ROC curve analysis was 32mmHg for the prediction of increased A-IMT (sensitivity 76.3%, specificity 63.5%). The area under the curve was 0.784 (95% CI 0.720-0.847, p < 0.001). Abdominal A-IMT increased at a significant rate in patients with HT. An independent association was found between MBPS and A-IMT, which can both be easily detected by ABPM and B-mode USG. The high MBPS level was considered to be a simple and inexpensive method for detecting subclinical target organ damage. A-IMT measurement should also be a part of abdominal USG, which is a routine examination in HT patients.

Experimental research on the characteristics of steam-water counter-current flow in the Pressurizer Surge Line assembly

To investigate Counter-Current Flow (CCF) characteristics in the Pressurizer Surge Line (PZR SL) assembly of the large advanced passive nuclear reactors, steam-water CCF experiments are carried out on a stainless steel test section, which is a 1:4 scaled-down model of the AP1000 PZR SL assembly. The inner diameter of the test PZR SL pipe is 90 mm, which also belongs to the large-diameter pipes, as same as the prototype PZR SL pipe, in the field of Counter-Current Flow Limitation (CCFL) researches. The present steam-water CCFL experiments are conducted under normal pressure and saturated temperature, with the PZR simulator collapse water level ranging from 350 to 900 mm. CCFL becomes severer at higher steam flow rate, and the most limiting CCFL effect locates between the PZR simulator bottom head and the vertical part of PZR SL pipe. The onset of CCFL and zero liquid penetration (ZP) are two critical conditions in the CCF development process, dividing the process into three stages: Before-CCFL, Partial-CCFL, and CCFL-ZP. According to the local CCFL conditions, the development of the CCFL process is also divided into four-regions since onset of CCFL. The present steam-water CCF data are well normalized in terms of dimensionless Kutateladze (Ku) numbers, and a Ku-type empirical partial CCFL correlation is developed. The comparisons of the present CCF data and partial CCFL correlation with the CCF data and correlations of former experiment researches validate that the present empirical partial CCFL correlation is conservative to predict steam-water partial CCFL in the prototype PZR SL assembly of the large advanced passive nuclear reactors.

Water Hammer Peak Pressures and Decay Rates of Transients in Smooth Lines With Turbulent Flow

Transient pressure peak values and decay rates associated with water hammer surges in fluid lines are investigated using an analytical method that has been formulated, in a previous publication, to simulate pressure transients in turbulent flow. The method agrees quite well with method of characteristics (MOC) simulations of unsteady friction models and has been verified with experimental data available for Reynolds numbers out to 15,800. The method is based on the formulation of ordinary differential equations from the frequency response of a pressure transfer function using an inverse frequency algorithm. The model is formulated by dividing the line into n-sections to distribute the turbulence resistance along the line at higher Reynolds numbers. In this paper, it will be demonstrated that convergence of the analytical solution is achieved with as few as 5–10 line sections for Reynolds numbers up to 200,000. The method not only provides for the use of conventional time domain solution algorithms for ordinary differential equations but also provides empirical equations for estimating peak surge pressures and transient decay rates as defined by eigenvalues. For typical sets of line and fluid properties, the trend of the damping ratio of the first or dominate mode of the pressure transients transfer function is found to be an approximate linear function of a dimensionless parameter that is a function of the Reynolds number. In addition, a reasonably accurate dimensionless trend formula for estimates of the normalized peak pressures is formulated and presented.

Altered Circadian Timing System-Mediated Non-Dipping Pattern of Blood Pressure and Associated Cardiovascular Disorders in Metabolic and Kidney Diseases.

The morning surge in blood pressure (BP) coincides with increased cardiovascular (CV) events. This strongly suggests that an altered circadian rhythm of BP plays a crucial role in the development of CV disease (CVD). A disrupted circadian rhythm of BP, such as the non-dipping type of hypertension (i.e., absence of nocturnal BP decline), is frequently observed in metabolic disorders and chronic kidney disease (CKD). The circadian timing system, controlled by the central clock in the suprachiasmatic nucleus of the hypothalamus and/or by peripheral clocks in the heart, vasculature, and kidneys, modulates the 24 h oscillation of BP. However, little information is available regarding the molecular and cellular mechanisms of an altered circadian timing system-mediated disrupted dipping pattern of BP in metabolic disorders and CKD that can lead to the development of CV events. A more thorough understanding of this pathogenesis could provide novel therapeutic strategies for the management of CVD. This short review will address our and others’ recent findings on the molecular mechanisms that may affect the dipping pattern of BP in metabolic dysfunction and kidney disease and its association with CV disorders.

Development and Decay Processes of Dual Inversion Layers in Winter over the Northwest Coast of the South China Sea

Abstract Inversion layers in the lower troposphere appear centered at two heights, 1.5 and 4 km, over the northwestern coast of the South China Sea in late boreal winter. The mechanisms of these dual inversion layers are investigated with thermal budget and composite analyses of the JRA-55 dataset. The thermal budget analysis classifies inversion layers between the levels of 700 and 600 hPa into two types. One type is related to high pressure moving southward along the eastern edge of the Tibetan Plateau; the arrival of the high coincides with subsidence that warms the 600-hPa level more strongly, and the stability increases between the 700- and 600-hPa levels. The other type is related to a synoptic-scale eastward-propagating wave in the upper troposphere. The upper-level high pressure in the wave is accompanied by a midtropospheric warm area whose intrusion at the 600-hPa level generates the inversion layers. Inversions between the levels of 925 and 850 hPa are related to heating and cooling by horizontal advection of potential temperature in the upper and lower levels, respectively. The vertical contrast of horizontal advection corresponds to a frontlike structure at the southern edge of a pressure surge. The pressure surge has a similar structure with the high pressure moving along the plateau edge as mentioned for the former type of inversion layers between the 700- and 600-hPa levels.

A Review of Experiments and Modeling of Gas-Liquid Flow in Electrical Submersible Pumps

As the second most widely used artificial lift method in petroleum production (and first in produced amount), electrical submersible pump (ESP) maintains or increases flow rate by converting kinetic energy to hydraulic pressure of hydrocarbon fluids. To facilitate its optimal working conditions, an ESP has to be operated within a narrow application window. Issues like gas involvement, changing production rate and high oil viscosity, greatly impede ESP boosting pressure. Previous experimental studies showed that the presence of gas would cause ESP hydraulic head degradation. The flow behaviors inside ESPs under gassy conditions, such as pressure surging and gas pockets, further deteriorate ESP pressure boosting ability. Therefore, it is important to know what parameters govern the gas-liquid flow structure inside a rotating ESP and how it can be modeled. This paper presents a comprehensive review on the key factors that affect ESP performance under gassy flow conditions. Furthermore, the empirical and mechanistic models for predicting ESP pressure increment are discussed. The computational fluid dynamics (CFD)-based modeling approach for studying the multiphase flow in a rotating ESP is explained as well. The closure relationships that are critical to both mechanistic and numerical models are reviewed, which are helpful for further development of more accurate models for predicting ESP gas-liquid flow behaviors.

ANALYSIS OF DEEP STRESS FIELD USING WELL LOG AND WELLBORE BREAKOUT DATA: A CASE STUDY IN CRETACEOUS OIL RESERVOIR, SOUTHWEST IRAN

To identify the wellbore instability of Bangestan oil reservoir in the southwestern Iran, the direction and magnitude of stresses were determined using two different methods in this study. Results of injection test and analysis of wellbore breakouts were used to verify the accuracy of the stress profiles. In this study the Bartoon method, which using the breakout angle and strength of rock, was used. In addition, the ability of artificial neural network to estimate the elastic parameters of rock and stress field was used. The output of the neural network represents a high accuracy in the estimation of the desired parameters. In addition, the Mohr-Coulomb failure criterion was used to verify stress profiles. Estimated stresses show relative compliance with the results of injection test and Barton method. The required minimum mud pressure for preventing shear failures was calculated by using the Mohr-Coulomb failure criterion and the estimated stress profiles. The results showed a good compliance with failures which have been identified in the caliper and image logs. However, a number of noncompliance is observed in some depth. This is due to the concentration of fractures, collisions between the drill string and the wellbore wall, as well as swab and surge pressures. The stress mode is normal and strike-slip in some depth based on the estimated stress profiles. According to direction of breakouts which is clearly visible in the caliper and image logs, the minimum and maximum horizontal stresses directions were NW-SE and NE-SW, respectively. Thses directions were consistent with the direction of regional stresses in the Zagros belt.

Study on Selection of Pressure Regulating Valve for Hydropower Station with Both Surge Tank and Pressure Regulating Valve

The transient process in the hydropower station with both surge tank and pressure regulating valve is quite complicated and also critical to operation safety. According to the pressure regulating valve working principle, the influence of the valve diameter on the unit speed and spiral case pressure was analyzed theoretically. Mathematical models of the surge tank and pressure regulating valve in the hydropower station were established based on the characteristic method. In a practical engineering, numerical simulation of large fluctuation and hydraulic disturbance transient process are conducted, verifying the correctness of the theoretical analysis. Based on the calculation results, three principles for selecting the valve diameter are concluded: first, making sure the unit speed meet the regulating guarantee requirements when guide vanes fast close; second, the maximum spiral case pressure of two times should be approximate to each other by controlling the superposition of surge wave and water hammer; third, the maximum flow of the valve should be as close to the rated flow of the turbine as possible. The principles are helpful for selecting the valve diameter in similar hydropower station.

Calculation of the hydraulic stroke in the Mlecva MHPP pipeline caused by sudden closing of the closer

Water hammer is a pressure surge phenomenon that occurs in pressurised pipelines as a result of a change of the flow velocity. This paper presents analyses of water hammer in the pipeline of mini-hydro power plant (MPP) Mlečva in Bratunac, Republika Srpska. The objective of this paper is to analyse water hammer in the pipeline as well as to asses risks to the system from pressure surge The paper presents a description of the problem, equations of water hammer mathematical model and water hammer analysis using the software SurgePRO (Transient flow analysis) and Bentley HAMMER V8i.

Nonlinear transient analysis of FG pipe subjected to internal pressure and unsteady temperature in a natural gas facility

This study investigates the response of functionally graded (FG) gas pipe under unsteady internal pressure and temperature. The pipe is proposed to be manufactured from FGMs rather than custom carbon steel, to reduce the erosion, corrosion, pressure surge and temperature variation effects caused by conveying of gases. The distribution of material graduations are obeying power and sigmoidal functions varying with the pipe thickness. The sigmoidal distribution is proposed for the 1st time in analysis of FG pipe structure. A Two-dimensional (2D) plane strain problem is proposed to model the pipe cross-section. The Fourier law is applied to describe the heat flux and temperature variation through the pipe thickness. The time variation of internal pressure is described by using exponential-harmonic function. The proposed problem is solved numerically by a two-dimensional (2D) plane strain finite element ABAQUS software. Nine-node isoparametric element is selected. The proposed model is verified with published results. The effects of material graduation, material function, temperature and internal pressures on the response of FG gas pipe are investigated. The coupled temperature and displacement FEM solution is used to find a solution for the stress displacement and temperature fields simultaneously because the thermal and mechanical solutions affected greatly by each other. The obtained results present the applicability of alternative FGM materials rather than classical A106Gr.B steel. According to proposed model and numerical results, the FGM pipe is more effective in natural gas application, especially in eliminating the corrosion, erosion and reduction of stresses.